Fuselage

I have found it quite difficult to organise the paperwork aspect of flying in a -4. With significant help from my wife I have constructed this easy access pocket for maps and flight guides. I first flew with it yesterday, and its a great if small success.

My battery is on the firewall so this front compartment, underneath the pocket, is for adjusting CofG and carrying heavier items when aft loaded. You can see it here also, without the map pocket.

As additional storage I have an easy access space under the RHS step.

Yesterday the wings went on without too much bother. Two of us did it in about 2 hours. That is to the stage where we had 4 of the large bolts in each wing and one of the outer AN4 that take the load.
I made one mistake. I have aileron push rod tube draft seals. They are on an ally frame on the outside of the fuselage with screws from the inside. The frame was upside down so the wing had to come far enough off to let us rotate the frame around the tube.
I had forgotten, since the trial rigging, just how close the wings and fuse come on the -4. Don't overestimate the space.

I guess the picture is of two ikons together; an RV4 and a Supercub. Double click as usual if you want a better picture.


It is a slow job putting all the bolts in. I have spent nearly two days at it now. I am stiff and bruised but the job is 95% done. I have put the bolts near the pilot seat cushion with the heads aft to save the cushion. The rest I have tried to arrange neatly, bearing in mind which way is easiest to do them up. VANS have overspeced all the AN3 bolts involved. There are some AN3-16 which could all be replaced by AN3-15, and similarly some AN3-17 which could be replaced by -16. As a result, as you can see there are plenty of washers involved. If you use the VANS supplied bolts be sure you don't tighten the bolts down to the end of the thread.
A couple of the NAS bolts were very hard to get in. There is no rhyme or reason as to why. Use plenty of grease. I also spilt quite a bit of ACF-50. It is not the worst thing to spill but I will have to get the degreaser out in due course.
I seem to be short of a couple of bolts and some washers. I will make a note and come back to this.


Here is another view of the centre section.

Much of my wiring comes through the wing spar beside the control column. I have yet to fix it up and out of the way. Once this is done there is room for both without interference.

In this picture you can just see the aileron draft boots. They are orange balloon fabric.

For completeness I have added a picture of the flap system and wing leveller.

The relay in the bottom left of the picture signals when the flaps are less than about 95% retracted.



And here is how it all looks from where the pilot sits.

I made up this bracket today to stand the throttle cable off the bulkhead. (I made a different design yesterday but had to throw that one away!)

I installed the 'Red Cube' FT-60 fuel flow transducer today. It is installed between the electrical and mechanical pump, and after the Andair gascolator which I am using as a fuel filter. They ask for 5" of straight tube before the fuel enters and the same after. I haven't quite achieved the former. but doubt this will be a problem. If it is I will just have to bend up another bit of ally pipe.

I wonder why they have the connection wire exiting the top. I would rather it had come out of any other face!.




Here is another view.



The corrugated duct in this picture, is to take electrics through the cut out in the spar. There is just room for this without interfering with the control column. It will need to be stabilised very carefully when the wiring is complete.
















I wanted to keep the forward compartment empty.
The battery is forward of the firewall. With the fuel related items above, located in the next compartment aft, with the stick, with the exception of the fuel pipe you see, I have this to use for a small bag, and also to adjust the CofG as necessary.

Labels: Fuel

After three weeks away travelling, its back to the -4. I installed the pitch servo. It is identical to the role servo, and presented equally well.

To install it, you replace the standard VANS bellcrank brackets with a pair provided by True Trak. This just requires some careful de-riveting and then riveting the new pair in. They are extended behind the bulkhead to support the back end of the servo.

After that it is very straightforward with all necessary holes already drilled in the supplied parts.

Here is a view from the other side. The note is to remind me that I have yet to adjust the pushrod length and install a nylock.

The weight of these servos continues to offend, but I have to say they are beautifully made.

My wife is determined to remain a passenger, not a co-pilot, so on longer journeys where I have to manage flying, navigation, map folding and airspace they will be invaluable.

As usual, if you want to see more detail double click the pictures.

I installed the Tru Trak role servo today. The servo is a beautifully made stepper motor. It is a bit on the heavy side but much more reassuring than the Navaid devices servo which I believe has been carried over to Trio.

It is a bit of a tight fit, but once it is in it appears to just clear everything. The large washer outside the bearing arm on the servo comes within about 1/16" of the underside of the floor, but I guess that is enough.

The total movement of the arm is a little less than 2", which is very little but appears to be what Tru Trak expect.

There is a very slight drag from the stepper motor when you move the stick, though once the push rods an ailerons are connected I suspect this can not be detected.

A helpful tip from a US builder pointed me in the right direction, and I chamfered the top corners of the bulkhead flange and the seat rail so the seat could tip back all the way to the bulkhead. Once this was done things started to fall into place. The major difficulty was the quality of the fiberglass part. It is far deeper than the canopy rail. I cut it and re glassed it.
Everything pretty much fell into place after that, though the seat is perhaps a little tighter than I intended at the top. I am not sure why, since I had a 1/8th " spacer in place throughout at the 12:00 position. Still better tight than flapping about, when flying solo in turbulence.
While my wife likes flying as a pax she would much rather not touch the stick! For this reason I wanted secure storage for it, out of her way. Once the seat went in, its home became obvious. It hangs on a pip pin, and is held at the bottom by a spare flap block. It is clear of the rudder cable also.














Postscript 19th March '09
Some interest in the finished rear seat has prompted me to post this picture. The cushions are by Becki Orndorf, and she did a great job.

This area is subject of an SB from VANS some 10 years ago. SB 97-05-1.
I think the SB caused the steel triangular brackets to be added, and they were not there before. They are standard on my plans. I think the purpose of the bracket is to stop the bulkhead collapsing backwards, and letting the seat, and buba, fall across the elevator pushrod. It is less than clear, because the SB refers to several figures which are not included.

I am a bit confused though, as to how the weight of the passenger is to be transmitted from the seat to the bulkhead itself. It appears very crude if the intent is point contact like you see in the second picture. I wonder what others have done?

I now have a complete path for fuel from the left tank to the fuel pump. If you are surprised to see the gascolator in this picture I have explained my logic elsewhere.

I am always amazed how simple bending pipe is in theory, and difficult to get it just right, with no stress, in practice! This is my best shot.

The path for the RH tank pipe is more complicated, and I am debating if I want to use pipe, or hose. Hose has a weight penalty but I could get there in one which provides less opportunity for leaks.

In this picture the part lying on the centre of the floor is a doubler plate for a bent whip antenna, but none of that is yet installed.

The continuation of the piperwork from the fuselage wall, to the LH tank, is shown in this "Wings" entry of the blog.

These brackets have been enormously time consuming. The problem is VANS plan is close to an irrelavancy, as I explained before. This is compounded by the practicality of the task. Do you drill from the inside to the outside, or vice versa? From the inside it is physically quite difficult. From the outside, the wing is in the way. Perhaps if I had an even smaller right angle drill.....

The control system in the centre fuselage is almost complete. The points to note are:

1) Earlier on this blog - see Jan 12th '07 & July 8th '06 entry - I considered making the F-449 bracket so that it moved the stick further forward. In the end I have used the bracket as defined by the plans, but added a 1/8" shim between the bracket and the tie bar. This has moved the aileron pushrod tubes forward so they are almost central fore and aft, with respect to the pushrod tube hole in the sidewall. Making a firm decision regarding this, enabled me to match drill the 4 bolt holes for the rear mounting point of the stick assembly, in the centre of the picture.

2) I still have to increase the clearance of the push rod tube as it exits through the side skin. It is not blocking full movement as the rod gets to the limit of its travel but it is just touching. You can see this in the picture. With the stick fully over to the left the RH push rod tube just touches at the top of the exit hole. If I relieve this by 1/16th to 1/8th, that will cease. It is the same on the left side.

3) I have had to grind quite a bit away from the hole above the rear spar, to ensure it does not touch, as you move the stick from side to side. I have an extra heavy bracket here to permit a 5th point for the PAX harness. I may need to grind a bit more off yet, to be sure it does not touch.








The flap mechanism went together quite easily, though the stressful bit lies just ahead; cutting holes in the exterior skins for the flap push rods.





Here is another picture of the fuse centre section.

Postscript - 12 May 07

For completeness I have added a picture of the manual aileron trim unit.

The way it works (I think) is so.

The stick runs through the centre of the UHM block. The RHS long screw serves both to clamp the unit to the stick, as a pivot for the trim arm (green) and to provide some friction in the system. The LHS screw increases the friction in the trim arm. The springs attach to the lower part of the trim arm and the other ends to the sides of the compartment in which the stick is located. I presume some locking wire is used to adjust the length / tension.

So if you move the top of the trim arm to the left, the left spring tightens and the stick is offset left.

(If you click on the picture you can get a bigger one, which will enable you to see more detail.)

One day this week when I was putting off the day when I had to drill the rear spar, I decided to cut out the brackets that attach the fuel tank to the fuse. I diligently marked out two, according to the plans, and worked away with my hacksaw. (Yes, I still haven't bought a band saw..its a hacksaw and file for me!)

Labels: tanks wings

I installed the F-449 bracket today. In fact I made up two of them, one per the plans, and the second one shown here. It locates the bearing, supporting the control column, 5/16th further forward. This appears to be preferential since it causes the aileron push rods to line up with the push rod hole in the side of the fuselage and wing rib. The standard bracket moves them 5/16th aft causing considerable filing to gain clearance for the push rod.

Labels: controls

This turned out to be a very easy task. We had expected it take the whole day. With a little grease on the bolts, and a very light wooden mallet, the whole job took less than 75 minutes without any swearing.

The only slight hang up was getting the rear spar to fit between the two 'ears' in the side of the fuselage.
It is unclear quite how many bolts you need to safely support the wings. We took the decision to install 4 AN6 bolts into each wing root, together with one of the AN3 and AN4 bolts on each side, to take the weight.





While waiting for help with the wings, I had started to look at the canopy frame. I think it will be several months until I return to this task, since installation of the wings makes possible so many tasks that need to be done.

The canopy work will be much more easily undertaken when the wings are back off.

The wing installation continues under the the 'wings' section of this blog.

Labels: wings fuselage

I have used the rivets that VANS supply in their static kit. The tubes are glued in with blobs of a proseal competitor product. Once the ‘proseal’ that holds the rivets on is completely set, I just need to cut the tubes to length, and proseal them onto the rivet tails. I was quite negative about this static approach and nearly shelled out for a more expensive (and heavy) solution, but I now feel good about these. I will leave the static line aft of the bulkhead for now until the interior, forward of it, has been painted with a topcoat.

The forward storage is largely complete. With the battery forward of the firewall I will have a useful storage container between my feet as well as the smaller area under the right hand step. The large aft part of the storage lid is hinged (from behind the two clecos). I am not sure how many camlocs to use to ensure it does not vibrate. The hole is to put your finger through in order to lift the lid once the camlocs are released.

A secondary but important aspect of this storage area it will enable me to adjust CofG by re distributing heavy items between this area and the main baggage area.

In the next area back where the stick is located the bracket on the front left is the mounting for an Andair fuel valve, and behind that the next bracket will have an Andair gascolator bolted on. My approach to the gacolator is that it will just take the role of a filter. I do not plan to drain it before every flight. Testing for water will we be done at the wing drains since this is by far the most likely location for it to occur.



The array of rivets in the centre of the bulkhead (see center of upper picture) is reinforcing for nutplates to hold the Facit fuel pump.

I made the front seat today. I had been very interested in the Jon Johansen seats, but the responsiveness of Flymore, his company, leads me to believe they are no longer interested to sell them. I begin to think I will go with the standard VANS seats.

I drilled a few extra holes in the angle, since in the spanwise direction it is way over engineered. It only saved a few grams though. You might just be able to see if you double click the picture.

At least now I can sit in and make aeroplane noises. Well, I didn't make the noises, but I did try it on for size, and was surprised how roomy it is in there. Perhaps I view it this way because I am used to glider (sailplane) cockpits. I am going to need a mountain of cushions to see out.

Here is another picture. As you see, I have put some small brackets in on the rear face of the second bulkhead. My idea is to insert plastic thimbles into these and use them for the main elements of the wiring loom.

I never understand instructions like these in the plans. It is embarrassing to be building my second RV and still not fully understand this!

In the plan it says to drill "D". This is slightly less than .25", the size of an AN4 that will go in there.

Is the idea:
a) You drill "D" then hit the bolt with a mallet? Ouch!
b) You drill "D" then ream to .25"? Normally VANS call for a reamed hole if thats what they want.

Why not just say drill to .25"?










Perhaps someone will help me if I ask on Vansairforce.

Postscript 24/9/06

There were 2 or 3 really helpful comments came in on Vansairforce. If this subject interests you, see : http://www.vansairforce.com/community/showthread.php?postid=73740#poststop

This picture gives a good general idea as to how far the interior of the fuselage has progressed.

The floors are all in place, and the cut out for the flap drive is complete. In the build manual it said to install the inner flap drive brackets with nuts since they were accessible. To my mind only accessible if you have the dexterity of an orang utang, so I have used a pair of nutplates at ALL four bearing locations. The mount for the rear control column bracket is 'floating' for now and awaiting a trial fit of the wings. It will be quite easy to secure that with nuts however when I can match drill the holes.

The left side floor is drilled #30, and I will install with LP-4 pull rivets. (They are lighter than nutplates.) The right hand side I have made removable, and installed #8 nutplates to secure it. These were difficult to install since you are working very close to the side skin which makes for great difficulty operating my Tatco. I have since learned that it is recommended these are installed prior to skinning the aircraft. I endorse this. A shame VANS don't mention it. I used some CCR-264SS-3-2 blind rivets in the most difficult places.

The reason I want the floor removable is I plan to have a wing leveler down there on the RH side, and will need accessibility.

Yes, if you are wondering, I have used 4 different etch primers. Mostly it is a biscuit colour, but there are also 3 different shades/brands of gray. From here on I will be down to 2 colours: biscuit ,and small jobs with a rattle can of gray.

Looking aft I have found a way to fix the upper rear baggage bulkhead. I am not sure what others have done. I made up some little brackets that stand the panel forward 1/2" and secured with #8 nutplates.

The rest of the baggage compartment is complete, though not installed in this picture.














I re did the throttle mounting by installing two very simple brackets. I think it positions the throttle in the right area, provides the necessary strength and is the lightest implementation I can think of.

I seem to have a different view of weight from most. Perhaps I will sound off in RAMBLINGS








I will not be covering it in because that only adds weight (and work)! This then is the final assembly. I have allowed for adjustment fore and aft, but I hope it is comfortable in the vertical.

I worried about how close to have it to the sidewall. It is hanging on 3/4"*3/4* angle and I think this will suit both my knuckles and thighs. We shall find out one day!








On my last posting here I said I would put a final picture of the forward baggage draw on the blog. I never did. I have put everything together so it will be easy to install the draw if I ever decide I want it, but with the main baggage area plus the empty hole called the battery compartment, I think I will have enough storage and capability to adjust the CofG.

When I ordered the fuselage kit I was still questioning if there would be enough room for adequate baggage, so I ordered the forward "Auxiliary Baggage Kit" - Plan 40. Its cheap. Since I plan to put the battery on the firewall freeing up the battery box for storage, and the rear storage area is bigger than I thought, I think there is enough room for my wife and I to travel with the things we want, without it. Looking at the kit however, it has become clear that it is very easy to install in such a way that it can be removed, leaving almost nothing behind and reinstalled for the occasional trip if I later decide I want it.

I thought it would be useful to put a few pictures here for any other prospective builder wrestling with the same issue.

If you are not familiar with it, it is a drop down draw, located between the firewall and the F-402 bulkhead.

In this first picture you can see the frame that 'contains' the draw. (All the unprimed bits.) It is attached by 4 nutplates to the cross angle on the firewall and by two nutplates attached to ears at each end of the F-402. I do not plan to go beyond the stage where it would be easy to install the nutplates and drop the assembly in at a later date if I ever decide I want to use it. It lifts out quite easily.

I notice you can also see that I have a removable panel. It makes it smaller but I see it as a real advantage. I will return to that sometime.


In the picture to the right the draw is sitting roughly underneath where it would fit with a hinge along the lower left side and some sort of retaining system to control how far it opens. (VANS are not very clear about their ideas for that.)







And in the third picture it is all removed, leaving just the 'ears' I installed to hold a nutplate. I wanted these anyway in preparation for the wiring loom. I plan that the loom will cross behind the F-402. I put some plastic thimbles in to make it clear what I mean.

I will finish the draw off in the next few days with clecos, and add a final picture, but then I will remove it.

The thing to remember is to try to keep the entire area it will occupy completely clear so it can easily be installed if I ever decide I want to. I think this plan might be somewhat compromised by the throttle and mixture cable but we will get to that in good time.

Getting fresh air into an RV4 judging by some of the posts on Vansairforce appears quite challenging. I ordered the newish vent design from VANS. It costs $18 for two of them. I thought I would put a picture here because, hopefully, it is easier to understand than the poor picture on the VANS website.

In the first picture the hole and backing plate is installed together with the brackets that support the door. In the second the door is installed and the retaining / friction bolt dropped into place.



It will be a couple of years before I can give you a test report but it looks as though it should provide a hurricane if extended into the airstream.


Here it is max open at 45 deg. It closes flush, and I hope that continues in use. The friction can be adjusted once it is 100% installed.

In fact I never use it for long enough to start taxiing but then I fly out of a small private strip. Perhaps it would be more useful on a hot day in Arizona!

Getting the rear F-440 push rod in was a puzzle. It runs from the bottom of the rear stick to the bellcrank half way down the fuselage. You can just see it in this picture....


...and also in this one.

http://www.vansairforce.com/community/showthread.php?t=9550

I asked what I should do, in the above link, and then did something different. I hope my fellow builders don't stop answering all my dumb questions in the future! They are a great source of confidence. My solution has been to cut a narrow gap in the top of the F-407 bulkhead. On the face of it this takes a lot of strength out of the structure, but in fact the plans show no join between the upper faces of this bulkhead above the push rod hole. (I might in fact put a removable strap to tie the two sides together. Then it will be stronger than shown in the plans.) With this bit removed, the rod just drops into place. I am advised that when I set the ailerons up I will have to enlarge the F-406 hole to allow full travel and this would also have allowed installation, but I was nervous of flexing the rod in view of some history. See : http://www.matronics.com/searching/getmsg_script.cgi?INDEX=31419437?KEYS=f-440?LISTNAME=RV?HITNUMBER=4?SERIAL=03075512942?SHOWBUTTONS=YES

As a complete aside, you can also see I have put a small drain hole in the floor. I hate doing this but I think water could leak in and collect here. Better it gets away. That's .0001 knots lost of my top speed!

Finally, while I am on safety issues, I have included this picture. You can see that I have locking wire installed on the flap motor. DON'T FORGET THIS!!!!

I haven't done it up yet since I am sure these parts will go in and out many many times before I go flying!

A posting on VANSairforce read,

"The other day on medium final my flaps (electric) went from full deflection to 0 deflection in an instant with a soft thud. I went around and checking things out and determined that I the motor was moving but the flaps weren't. An uneventful landing was made. "



See http://www.vansairforce.com/community/showthread.php?t=9458 for the full thread.

I was pretty sure I knew what the problem was, since I had built a -9A, and those plans ask you to lock wire the flap motor - see Detail E in the bottom LH corner.

Its a pity though that VANS don't have the same care for RV4 drivers. My flap motor plans for the -4 only came last year, and dont have this reminder! I had forgotten, and see no reason why I would have remembered in the next two years prior to flying. I hope this is helpful to someone else.



Postscript 14 April '07 - Finally a service bulletin has come out concerning this issue. See http://vansaircraft.com/pdf/sb07-4-12.pdf

I was planning to work on the elevator circuit but I was sidetracked into the power controls by access to a bending break. I will return to the stick assembly shortly.



The RV4 plans have poor definition as to where the quadrant should be mounted; or at least everyone disregards the position indicated as being crazy.

I made up this bracket. My idea was that I wanted the control canted outwards so my knuckles were not getting involved in the cockpit rail, but leaving maximum room for my legs. Now I am worried that the whole unit is to far out from the side skin.




I am also concerned about fore and aft positioning though I have allowed for this by drilling two extra sets of holes for the bracket to attach to.

Finally height is a concern though I can change things at the moment since the bracket is currently only held on with masking tape.







I think I will ask existing RV4 drivers for comments.

(What a shame they don't make the middle knob in blue. How cheap is that!)

I spent a bit of time making the rudder pedals. The result has turned out OK, but the drilling accuracy of the various pivot holes is crucial. What is odd is the fact that the brake pedals and the rudder pedals do not operate in quite the same spanwise plane. You will see when you make them!

I also drilled the holes through the wing spar bulkhead for the rudder cables.

Progress has been slow since it is so hot!

Next week's job is the elevator circuit. Today I trimmed the brass bushings to length, found all the parts, thought.......and decided it was too hot for further work. Went flying!

I advised VANS of the problem I was having. This was their response.

"I've heard that in some cases the ears seem to be too far back like
this, I don't know why; maybe the plans, maybe the parts. It's usually
not necessary to do anything. The fore and aft movement of the
pushrods is negligible at the fuse side, and it doesn't matter if they
are centered in the hole or not, so long as they have decent
clearance (say 3/16" min). If they don't, the hole can be enlarged a
little.

You can leave the weldment mounted the 7/16 further forward, I
doubt it will affect much. The stick won't hit the panel if you move it
forward, it goes under it. It's possible the rear stick will hit the front
seat back though; you may need to increase the curvature to clear."

I have now made two brackets. The one to plan, which caused the problem, and one that moves the mounting bearing 7/16" forward. I tried to simulate the location of the aileron pushrod today to see how it will actually position through the holes. It's a smaller diameter rod than used on the -9A I had, so this will reduce the problem.

What I have decided to do is not drill the holes that locate the rear support for the control column, until I test fit the wings, and then decide which bracket I want to use. By adjusting the height of the front bearing (I cant find that defined in the plans) it might just be possible to use the VANS defined part, though it locates the 'ears' on the aft limit. My concern is the geometry of how the sticks fit, though I do not perceive this to be a major issue.

I have run into a problem and I would like to hear how other -4 builders solved it. As you can see in this picture I have started to install the control column. (click on the picture and you will get more detail.)

I have followed the plans (I think, and the result is that the 'ears', to which the aileron push rods will attach, are sitting slightly too far aft to be central in the holes in the side of the fuselage. (This problem will compound the problem for the very tight space for passenger footwells.) Again I think the issue is probably generic (i.e. VANS) and not poor workmanship on my part. Has anyone met this problem before?

In this picture you can see the F-449 bracket to which the control column is attached. It is spaced forward as indicated in the plans by a 1/4" spacer to simulate the steel tie bars (not sure of the correct name) that join the wings. However, you can also see in this picture that the 'ears' are sitting too far aft.

I can think of several ways to solve it, but as always, I worry about problems that will result that I have missed:

Solution 1 - use a thicker spacer. The down side of that is I will need longer NAS bolts which may/may not be available.

Solution 2 - (better) remake the bracket with a longer tongue so the bearing is moved forward. Will either of these solutions leave me with enough forward stick movement? Will the bracket still be strong enough?

Solution 3 - I am screwing up, and the problem lies elsewhere. (Unlikely because I have been warned of the problem in the past though I forget who told me.)

Solution 4 - Have the 'ears' re welded slightly further forward. (Not attractive to me.)



In this picture you can see the 'ears' about 3/8" to the right (aft) of where they should be.

As a final note, yes, in the first picture you can see that I have made the bracket taller than normal with a hole in the top. This is for the harness 5th point.

Finally I finished turning the F-428 step into a step, with storage space underneath. Its a useful size. I threw in what was to hand in the Supercub. A thick flight guide, two passports and a digital camera case, and there was room for plenty more. Certainly a flask of brandy!


Here it is closed. I was hoping it would be less noticeable that it opened, but perhaps when it is all painted up and the canopy is on it will be.

The hinges and fore and aft bracing angle made it much heavier that the ordinary step, but then perhaps I have made it too strong.

I think I will put a 3/4" hole in the front left corner to facilitate opening and I will have to dream up a way of locking it shut. I don't want the brandy falling out when inverted. People will get the wrong idea.

I plan also to put a cover on the battery compartment and move that onto the firewall. It should all help put the C of G where I want it as well as provide storage for longer trips with Imelda.

Installing the floors progresses well. After preparing what seemed like a million holes the easy back riveting was quite rewarding.

Some issues have come up though:



First, here you are looking aft at the floor area where the passenger's bum will go. The flap drive is placed loosely in position. What VANS don't tell you in the instructions for the electric flap, is what they propose you should do about the floor that remains after you have removed the bit that interferes with the drive lug hanging down off the bottom of the shaft. Any one got a bright idea? Somehow just leaving it floating does not seem quite right.

Second, I am really not sure what to do about the two bolts that go through the edge of the lightening hole. If I do them up tight it will crush the stamping which is rather ugly. Ideally one would make a shim but it is just two complicated a shape to be practical. The bolts are where the plans dictate so I cant be the first to run into this issue.


Finally, I have decided to use the space under the step on the right as a storage hidey hole for bits and bobs. Has anyone got a picture of how they implemented this? I think opening to the right is the most practical way, and probably hinging the part in line with the fuselage centerline about 1/3rd of the way from the outside skin at the bulkhead. Good design is never easy so I would rather steal an existing satisfactory solution.

The footwells were completed today. One of those jobs that appears to be a lot of work for what it is. Its mostly back riveting though which is always satisfying.

Although not supplied by VANS, even as an option, most RV-4 have footwells for the passenger's comfort. It is worth noting they are pretty well mutually exclusive with rear rudder pedals. (But then you don't build a -4 with the emphasis on someone else having all the fun!) Plans for these footwells can be found in 'RVator 24 years'.

The footwell is riveted together from 3 bits of ally with simple bends. It then has to be set into the floor and a hole cut to size.





Here it is now dropped into the floor. Its still looking a bit
ragged at the edges but nothing a file and patience wont sort out. The black tape is to protect it from the file.

This is the crucial bit. The footwells sit right behind the aileron pushrod path. Once the footwell is set in the floor you need to check the path for the pushrod is clear. Yes, it overlaps a little, but I think this is normal.

One irritation shows up in this picture. You can just see a nut. This is a part of the flap system. It is where it is meant to be according to VANS plans but if I tighten it up it will crush the stamped metal around the push rod hole. It probably doesn't matter, but its a bit ugly.

Today I moved on to the flap drive system. I like mechanisms so this is where the fun really starts. The RV4 was originally designed with a manual flap system, however it has some draw backs, in particular its effect on passenger comfort. The electric flap system is therefore an option which was designed in afterwards. As you can see it uses the same flap drive mechanism as the other RV, but has an interesting lever system in view of the limited space.

In this picture you see the drive mechanism on the RHS partially extended; perhaps 10 to 20% of its range. The fixing on the LHS is a pivot point. About 1/3rd of the way along the lever you see a bearing which when the flap motor causes the mechanism to contract moves at about 1/3rd of the rate with 3 times the force. This pulls on a lug attached to the flap actuator (black) and in turn will cause the flaps to be deployed when it is all connected up. The points to watch when you are installing this are that you don't let the motor get too high. The problem this causes is the drive mechanism when fully extended is very close to the floor. I have a shim under the white nylon guide block you can see on the RHS. This will I think ensure the bolt head never touches the floor.



Here the camera is nearly on the floor, looking aft. You can see the same bearing on the lever arm and the lug hanging down to which it will connect.

You can also see something interesting which is nothing to do with the flap mechanism. Projecting forward towards the camera is my solution to the rear passenger 5th point seat belt attachment point. Its not ideal in that the pull will be vertically upward, but I think it is quite beefy enough to do the job. It will need a thin shim between it and the underside of the cockpit floor.

There are quite a few 2 man jobs involved assembling this since some of the brackets need riveting on from underneath the fuselage.

I spent quite a bit of today working on the role bar support structure. The role bar is now clecoed in its final resting place. All the necessary edge distances are good.

The canopy rail is installed and the F-417 is riveted to the bulkheads. I will need to replace the remaining clecos with blind rivets. A few are allowed, though VANS encourages you to buck as many in the space between the skin and the F-417. I cant make that work.


It is not clear that VANS intended the row of 3/32nd C/S rivets shown here, but it can't harm, and makes for a neater job with the rail pulled down tight on the skin.

Support came flooding in from the -4 community regarding the roll bar support structure. Several pictures all of which agreed with each other, and not quite with the plans. That has enabled me to move forward with confidence. (Thanks everyone!)

This is current status.













The angle is riveted to the F-417, and it sits nicely underneath the canopy rail. The forward inch or so even tucks in behind the rail which I think will make it look neater. I no longer need the shim I had made. The need for that went away when I 'unbent' the rail and was able to slide the angle up to its final location. It seems to be going together quite nicely now. The roll bar is sat there for the photo. I haven't touched it with the drill yet.




I still have to cut off the excess material from the flattened out side rail.












In this picture you can see the angle did fit nicely behind the rail at the front end, though not by anything like the amount the plans indicated.

In the first picture I have assembled the F-417 and replaced the canopy rail F-416. I have then offered up the 12"*1"*1" angle. The problem is that according to the plans about 1/3 of the angle should be behind the canopy rail. Even at the front nearly a quarter inch is sticking out.










In the second picture I have added a .063 shim to the F-407 bulkhead before attaching the F-417. The fit is now better, though none of the angle will fit behind the canopy rail. It will be just about flush at the front.


My question is what have I done wrong, or is it a figment of VANS imagination that about 1/3rd of the angle will be behind the canopy rail when slid into place?








For completeness, here is the shim.