B

Beardy

I'm New Here
Hello,

I have read that the new pre punched kits are so good that provided you put the panels together and they fit, there is no way that the structure will be seriously malformed or twisted. However, given that an RV4 is a more involved building project, I assume that there is much more scope for a screw up that would result in something that is warped or twisted. So my question is beyond the normal recommendations of taking an experienced RV builder with you, how would one evaluate the potential purchase of a part build RV-4?

I should state that my interest in a part built project is the potential to save time and money while enjoying some portion of the build experience. I am also considering an RV8, and if I were to build this would be probably a better choice. But I have heard that a 8 may not be the most comfortable fit for someone my size (5'7" 160lbs). I don't want to buy a flying aircraft, though I realise this is probably the lowest cost approach.

Many thanks
Mike
 
Hi Mike...whew...

...difficult to give you a short answer.

Aircraft rivets have a spec they have to be driven to. An 1/8'' rivet should be 3/16'' shop head (Not the one that comes from the factory.

Workmanship involves many things, like the builder laying out the rivet lines with a straight edge and spacing them evenly with a template or good ruler...I've seen horrendous work...rivet spacing randomly done...3/4" here 1 1/4" there and wavy lines with no ruler or straight edge used...miserable work.

Thats part aesthetic but could affect the integrity of the structure, so take a good look and preferably, another builder or A@P to check it out.

You'll find quite a few guys on here that'll accompany you to do a pre-buy inspection as well. There's a big RV contingent in Socal, so you shouldn't have a problem finding someone.

Regards,
 
Beardy said:
I am also considering an RV8, and if I were to build this would be probably a better choice. But I have heard that a 8 may not be the most comfortable fit for someone my size (5'7" 160lbs).
Click to expand...

I'm wondering why someone would say this - the RV-8 fit s lots of folks that size just fine. You'll obviously have more room than someone with more bulk, but that's not a problem - I have much more room than I need (5'8" 175 lbs), fit perfectly from a height standpoint, have great visibility over the nose...and if you feel you need a little more height, you can adjust that with cushions. If you feel you're getting bounce around a "too-large" cockpit, you just tighten down your harness a bit.

the -4 and the -8 really have different missions - I'd look at the one that best fits yours.

Paul
 
Things to look for.

Mike,
Carefully inspect the the lower firewall for cracking. This is a common problem on RV4s. It usually happens near the engine mounting points. There was an update on the engine mount structure located behind the firewall. See if this has been incorporated into any kit you consider buying.
Also, there are two landing gear lengths. The shorter legs came with the earlier kits, the longer legs with the later kits.
An RV8 would be easier to build. Why would you think that an 8 would be uncomfortable for you?
Charlie Kuss
PS Info on the engine mount structure update and other good info can be found in the 27 YEARS OF THE RVATOR. See
http://www.buildersbooks.com/products/act002/
Reading all the info in this publication regarding the RV4 will really help you in your decision.
 
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fit in an RV8 for vertically challenged pilot

Thanks for the comments and input.

I read on this forum and then confirmed it with the original author that the rv8 was more comfortable for larger folk and that the stick position was not ideal. One comment I have heard was that it needed to be far forward for spin recovery and at the limit of ones reach if short. I need to get in one on the ground to see how this pans out and try RV4 on also - this may be inaccurate or just one opinion that doesnt necessarily reflect the majority.

One key aspect with the choice of an RV4 versus 8 is the cost to build (or part build). The 8 seems a lot more expensive, although the pre punched kit would appear to be more idiot proof. I would like to build and perhaps this bit is particularly strange, but I am not yet ready to have the plane in a hanger - I am actually looking for a garage project for a while. However, I am less fussed with building the complete airframe compared with having my own input in the firewall forward and wiring. A part built project seems the lowest cost way to get into an RV short of buying a flying plane, but because of the kit differences the RV4 seems a lot more subject to builder input (positive or negative)...

Thanks again
mike
 
Four More

Having built and flown an RV4 for 12 years and 1400 hours and flown all the other RV's including fifty hours in the -8, I fully agree. The RV4 is the best flying RV "bang for the buck" out there. For a person 6 feet or less tall and under 200 lbs, it fits like a glove. Bigger than that and I recommend this aircraft over the RV8, hands down.

www.harmonrocket.com

Smokey
HR2
 
I hear you Smokey, but I suspect if you could have a civilian F16 you wold be recomending that over the Rocket! I suspect both are beyond me as a first time builder and I would like to keep a) the budget within sight and b) be able to afford to take this thing up now and again....

I have read about the potential for an F4 and I favor the mazda wankel. So what I am reeally looking for is a modestly priced half built fast back RV4 or F4, but I really need to do my homework and look at a few in the flesh first.

Buying an RV4 project just strikes me as a little more speculative in as much as you are relying on the individual to measure and build to plans rather than a punched out RV8 kit...
mike
 
Beardy said:
I hear you Smokey, but I suspect if you could have a civilian F16 you wold be recomending that over the Rocket! I suspect both are beyond me as a first time builder and I would like to keep a) the budget within sight and b) be able to afford to take this thing up now and again....

I have read about the potential for an F4 and I favor the mazda wankel. So what I am reeally looking for is a modestly priced half built fast back RV4 or F4, but I really need to do my homework and look at a few in the flesh first.

Buying an RV4 project just strikes me as a little more speculative in as much as you are relying on the individual to measure and build to plans rather than a punched out RV8 kit...
mike
Click to expand...

Beardy,

If you change your mind about a Rocket (HR II), I'm looking to switch to one of the side-by side RV's. I have an empennage about 90%, wing spars and center section bulkhead done, flaps & ailerons ready to rivet, right wing in the jig working on tanks, and most parts to finish wings except pitot and tips, including 1-piece top and bottom skins. I'll let it go for $3400, which is half what Vans is currently getting for RV-4 empennage and wing kits.
 
Bang for Buck

Mike,

I'm really encouraged to read your rationale for wanting to build an RV-4 from a partially completed kit. I agree completely - and I'm looking to do likewise. It's probably true that the cheapest way into the air is currently to buy a flying airplane. Such is the state of the economy these days that airplanes seem to be selling for less than the sum of their parts. Nevertheless, I want to build, and if price is a factor then completion of a partially-completed kit makes pretty good sense. My rationale is as follows:

1. I want to be involved in the construction of my airplane to a sufficient extent that I develop the skills and experience required to provide for its life cycle support. There is peace of mind to be found in knowing how your airplane ticks and being able to fix what breaks. This comes from hands-on experience;

2. If you compare the prices of partially-completed kits with the new materials from Van's, there is a negative return on investment for the builder's labour. I ran some numbers recently from ads on Barnstormers, and found that partial RV kits sell for, on average, 67% of the retail cost of the kits from Van's. That number is subject to wide variance, with newer models retaining value better, and nearly completed kits selling for more than nearly new kits. Nevertheless, they represent good value;

3. Considerable time can be saved; and

4. The opportunity remains to make most of the customization decisions that truly personalize one's airplane.

As for the choice of RV-4 versus RV-8, I foresee the biggest factor being baggage space and payload. If you and your passenger are of "average" size, and you can limit yourself to about 40 lb of luggage, then the -4 should suffice. Workmanship is a factor on any kit, in my opinion, and a qualified inspection is essential.

My opinions, FWIW,

Rob
 
2 cents

Mike, the 8 kit is $20,530 the 4 is $16,040 if you use the same prop-engine and avionics the difference will be just under 5k. The 8 is prepunched and much easier to build, it is roomier and has a higher resale. Ask Smokey what an 8 can do on 150hp with a C/S prop. Now having said that, I first built a 4 and I have flown them all except a 3, I am building another 4. Yes you can get a deal on partially built kits, you are in So Cal and have a huge RV builders base, if you want some names just ask. It?s a lot of personal preference and what your mission is. I was on a budget and couldn?t afford a new engine, so a bought a core, had the bottom end overhauled by an AI, put overhauled cylinders on it, mags gone through and new fuel pump, all AD?s done, it was a ?certified? engine. I had $8,900 in the engine. It still had a 2000 hour TBO. Keep it simple and light, not really sure about the wankel engine. If your ever away from home and it had a problem, where would you get help and parts? Airports with maintenance facilities will have parts and knowledge of a Lycoming, help is readily available.

I have a friend that has wings and partical tail with Flogisten? Spars, asking $2800.

Happy riviting, its worth it!

Randy
 
Here's what I'd look for

Mike,

It seems this topic has gotten a little off thread. Here's what I'd look for - everything Pierre said plus these things.

Empennage:

Make sure the elevators will mate up correctly with the horizontal stabs. Same with the rudder/vertical stab. If the builder was sloppy, they may not match up real well. You could have a case where one of the elevator bearings will not fit into the hinge brackets on the horizontal stab if that makes sense.

Make sure the rivets comply with the edge clearance distances - in other words, the rivets can't be too close to the skin or rib edges or you're asking for cracks.

Wings:

Check for the same things, but also make sure the wings aren't twisted. If the fuselage is in the construction phase, make sure the wings will mate up with the fuselage. The key here is that the distance from the front spar to the rear spar matches the actual gap of the same in the fuselage.

Hope this helps . . .

Rick
First flight tomorrow!
 
4 versus 8 comparison

Mike,

One must first decide what the aircraft 'Mission Objective' is going to be. Then decide on the RV (or otherwise) model to fit that role. There is a lot of overlap on potential mission requirements on the -4 and the -8/8A.

Some food for thought... The -8/8A will build considerably faster because of the nature of the pre-punched kits. In addition the -8/8A is also available as a Quickbuild Kit. Wings and/or Fuselage. The -4 is not. The -8/8A will certainly haul more baggage. The -4 is overall a quicker handling aircraft than the -8/8A. PAX comfort is better in the -8/8A.

I would suggest to try to get a ride in both and then decide...

Also read these regarding used kit/aircraft purchases:

http://vansaircraft.com/pdf/usedrvkit.pdf

http://vansaircraft.com/pdf/buying_a_flying_rv.pdf
 
Mike,
Depending on where you are in Socal, I might be able to help you out. I've built a -7 tail, and bought a built -4 tail and partially built wings i'm *kinda* working on right now. Everything is at KPOC if you want to come down and have a look. I can at least show you what red flags should go up.

I've thought about selling my -4 kit on an off since it's too far along to make a Harmon out of it, and thats kinda the direction i'm headed, but I got it for such a steal it's hard to justify that.
 
Been there, done that...

Mike,

I am fortunate enough to look at alot of RV's with my consulting service, many of them RV4's. Having built my RV4 back before the internet, I start any inspection with four questions.

I ask the owner before I start looking:
1. Why are you selling it?
2. Any damage history?
3. Did you build it?
4. Any liens against it?

Then I start looking. Get it in bright light, outside is preferred. Start by looking at every rivet. Yep, every one you can see. Sight down the wing, top and bottom looking for twist or uneven patterns. If you haven't looked at one before, take someone along who has.
Look very closely at the tail, especially the forward ribs on the horizontal stabilizer. You can use pop rivets there, just make sure they are installed properly. Look for "smiles" indentations around rivet heads or rivets sticking up.
Fuselage: Firewall attachment, look for dents or bends on the SS. On flying airplanes I look for the buckled rudder pedal wells from hard landings. Not a show stopper, but you then need to look closer at the lower engine mount longerons for cracks and for bent landing gear.
Controls: Look at every rod-end bearing and check every nut for tightness. Look for hangar rash on trailing edges or drilled holes for no reason, anywhere!
Firewall forward: FAR part 43 is the guide for standard practices, read it through and a copy of Tony Bingelis' book. This will help you when you inspect.

If you have any questions, email me off line anytime.

Smokey
HR2
 
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