Mike D

Mike D

Well Known Member
What are your thoughts on builder mods when you are looking for a plane to buy?
I know, it depends. But what is the tolerance?
A simple fast back on a -8 should be okay (I think) but what about changing the -10's door to open like a Cirrus? Or how about re routing the rudder cables slightly like moving them in the -10s tunnal completely?
Or how about removing the rudder control horns and using an internal rudder system?

Just thinking for now :)
 
Mike D said:
...Or how about removing the rudder control horns and using an internal rudder system...
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The other things are kind of down in the weeds, and mostly fall within the capacity of a conscientious craftsperson to develop and execute responsibly. But I would draw a solid red line when it came to fundamental changes in primary flight control systems. Van and his design and engineering team have done a great job at developing control systems that are simple and effective in addition to being easy to build. I would not second-guess their work without a rigorous engineering analysis of the system, and of its interfaces with the airframe's structure and other systems.
 
Bob Kuykendall said:
The other things are kind of down in the weeds, and mostly fall within the capacity of a conscientious craftsperson to develop and execute responsibly. But I would draw a solid red line when it came to fundamental changes in primary flight control systems. Van and his design and engineering team have done a great job at developing control systems that are simple and effective in addition to being easy to build. I would not second-guess their work without a rigorous engineering analysis of the system, and of its interfaces with the airframe's structure and other systems.
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Fuel system mods would be major point where you would need to stop, inspect it in great detail, and make absolutely certain you understand it and agree with it. I've modded my fuel system, and I've fully accepted that it may impact me if I try to sell it.
 
I agree every mod would need to be okay from a structural or safety perspective. But I may slightly disagree that Vans has done it perfectly.

There are many other aircraft out there that have different or even slightly better ideas than Vans. I think vans have done things a certain way to accommodate an easy build or because that is what they had in their tool box.

This is experimental, and I can almost do anything I want to, but this may not lead to a good resale value. So I am trying to gauge the tolerance of the vans community.

Modified fuel systems would need a good reason. Not sure i can think of one.

But looking at Velocitie's and RV-10's, the way the gull wing doors have been done have caused accidents. The Cirrus style door would have prevented these accidents.

Others make a business out of fixing the perceived shortcomings of the Vans design. Nose wheel comes to mind.

To be specific, I am thinking of building a -10 and like some of the features of the Cirrus and Lancair's. I would like to incorporate these into the build. I would have most likely gone for the Lancair ES except for the rear seats and the stall speed.

Of course I never intend to sell a plane I build, but I am sure it will outlast me.
 
Answering the question directly, mods will in general affect the value of an RV being considered for purchase to import into the UK. We are more regulated over here, and all "mods" need to be approved via an assessment process.

Quite a few RVs are imported from the USA into the UK, although I doubt it is a significant % of US to US sales?

I would only echo the oft quoted words that mods in general cost more and take longer to implement, for less eventual benefit than are envisaged. That does not stop any of us still thinking we know best :D
 
You're the Manufacturer, Now You Want to be the Designer

Can you? Sure! It's an EAB.
On the other hand, you've sold your aircraft to famous country singer John Colorado, and he's managed to crash it. His family drags you into court because it's America and because the new fuel system that you designed perhaps contributed to the crash.
You take the stand and it goes something like this...
Mr. Smith, what engineering school did you go to? When did you graduate? How many years have you been an aircraft fuel systems designer?
Mr. Smith, Van's Aircraft has about 8,000 aircraft flying with a fuel system they designed. You're telling us you did this because you wanted a unique design? Tell us about your decision not to affix placards to your new fuel system. You've stated that you "told" Mr. Colorado about the fuel system. Can you produce a record of this conversation? Etc. Etc.
You tell the court that it was an Experimental aircraft and Mr. Colorado knew that, but the darn lawyer keeps wanting to point out that you're the builder and designer. Hope you've got a big insurance policy and deep pockets, because it's probably going to cost a lot, even if you "win".
And BTW, the guy at Van's who's responsible for the fuel system design will probably be brought in as an expert witness to refute your design. Not because he doesn't like you, but because he's protecting Vans from joint and several liability.
If you've never given a deposition, it's a little like getting your teeth drilled for 6 or 7 hours. Memorable, even it you do come out with a brighter smile.
Back to the original question: If the mod you're thinking of doing involves a system or control, I'd think long and hard before I'd consider buying your airplane, but someone else may not give it a second thought.
Terry, CFI
RV9A N323TP
 
I don't like it but...

My insurance forms asked if the aircraft was built per the plans. Mine was but I'm sure there are higher rates if not.
 
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Terry, now your scaring me. Guess the same could be said about installing an Andair fuel valve instead of the vans supplied one.

Andy, good point. Never even considered the import thing. Is this a big problem or just a inconvenience?

Humm... My insurance never asked if it was built to plans. It was (for the most part)

Interesting , but scary, offline point.... "The paint job can add or detract more in resale than most mods."

Guess it goes to the old advice... " build the plane you want"

In Van's review of a specific -10, seems he was more critical of the added weight than most of the mods.

Okay, now I just need a couple of hundred grand for the -10:)
 
Not built per Design effect on resale value

First of all the systems design is not complete. In the RV-6 there is a statement to the effect that the company is providing a specific airframe for the builder but the firewall forward decisions, configurations and implementations are up to the builder. On that design at least no two are alike and some are crude. The same is true of the instrumentation and avionics systems. The concept of an airplane conforming to a specific configuration defined by a set of drawings and specifications applies in a high level sense only. There is no configuration control system basis for much of the airplane beyond the airframe itself.

Any buyer must thoroughly inspect and test an airplane and evaluate (note "Value" is part of that word) the airplane and all of the systems as a specific physical, functional and performance unit of amateur built production. The statements that it was built by an engineer or an A&P or an artist means nothing. It is the specific airplane under evaluation that must stand on its own merit. Any basic deviation from the basic airframe design must be looked at with a very critical eye and successful time in service and indications of problems and potential problems must be a part of the evaluation. Deviations from the basic ingress and egress systems should receive extreme attention in the evaluation.

What the buyer probably wants is a plain vanilla example of the airframe with the best selection of options and above all else good quality workmanship and systems integration. Conspicuous builder mods can effect the value either way. Well thought out and implemented mods that are well documented and obviously improve form, fit or function could increase the value and undocumented frivolous mods with no demonstrable benefit would reduce the value.

I have made many modifications to our RV-6A and I always have a functional, performance or quality improvement objective. I try to select the best approach for achieving it in a way that is both high quality permanent and reversible if it doesn't work out. The ability to make mods and test them is a very attractive part of the EAB experience for me and I would not surrender that freedom willingly.

Bob Axsom
 
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Andy, good point. Never even considered the import thing. Is this a big problem or just a inconvenience?
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In some ways it's a "non-problem" - if the mod is other than trivial, the UK buyer would be advised to not buy that aircraft. Does not stop some buying and then having to "undo" the mod :eek:
 
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