[FresnoR]

Well after months of researching just about every homebuilt kit available, I am about to take the plunge and order my RV-9A kit. I would like to thank everyone on this site for the knowledge you have all imparted to me.

My question stems from today?s economy. Do you think the downturn will cause an increase or possible decrease in the prices of RV kits? It seems to me the slowing demand of general aviation and luxury items such as homebuilt kits would ultimately result in lower prices, or maybe that?s just wishful thinking on my part since I'm about to buy one.

What do you think?

 

[sprucemoose]

While demand may or may not decrease, the cost of raw materials is certainly going to continue to increase. Van's is known to operate on fairly slim margins to begin with. So I would not hold my breath waiting for the price to go down.

 

[FresnoR]

raw material

Yeah, I figured prices would be dependant more on raw materials than anything else. Too bad their not made of wood, those raw prices have plummeted.

 

[bsacks05]

If I were buidling another plane - which I am. I would plan on installing a powerplant which will run on mogas. The cost and availability of 100LL is probably the greatest concern to piston powered aircraft owners. The prices of all the other stuff will remain the same or rise as with all other consumer goods.

 

[kentb]

Sense....

The average build time is in excess of 5 years the current economic condition may end up having very little to do with the cost to complete your plane.

Good luck.

Kent

 

[asav8tor]

Since he has people that "buy" the materials and various items that go in the kits at volume, you could not duplicate the kit with raw materials at the prices he sells it for. It's as if you get all the fab for free. The margins have always been small.

 

[the_other_dougreeves]

If I were buidling another plane - which I am. I would plan on installing a powerplant which will run on mogas. The cost and availability of 100LL is probably the greatest concern to piston powered aircraft owners. The prices of all the other stuff will remain the same or rise as with all other consumer goods.

I would second this - Mogas isn't exactly the fuel of the future, but it certainly is one fuel of choice for today. Make sure you can use at least 91 pump octane mogas (87 is ideal, but not always achievable) and make everything compatible with at least E10.

TODR

 

[frankh]

Both are easy to do

I would second this - Mogas isn't exactly the fuel of the future, but it certainly is one fuel of choice for today. Make sure you can use at least 91 pump octane mogas (87 is ideal, but not always achievable) and make everything compatible with at least E10.

TODR

With the bog standard lycoming clone with 8.5:1 pistons or less.

Frank
IO360 now featuring E10.

 

[frankh]

See post above

If I were buidling another plane - which I am. I would plan on installing a powerplant which will run on mogas. The cost and availability of 100LL is probably the greatest concern to piston powered aircraft owners. The prices of all the other stuff will remain the same or rise as with all other consumer goods.

With the right choice of componentry this is very easy to achieve with an IO360.

Frank

 

[airguy]

You'll want to eliminate ALL RUBBER ANYTHING in the fuel system, from the filler cap to the engine manifold. Ethanol in mogas will do a number on the rubber, it's the main reason certified aircraft need an STC to convert. Alodine ALL the fuel-wetted aluminum parts in the entire fuel system (don't forget the pick-up tubes and vent lines). Injected engines seem less prone to vapor lock with mogas than carbs due to higher fuel pressures. There are other items to be done as well to make the engine happier, but some are controversial and you'll get opinions on both sides.

My opinion only - worth what you paid for it.

 

[jonbakerok]

Alodined fuel lines?

Alodine ALL the fuel-wetted aluminum parts in the entire fuel system (don't forget the pick-up tubes and vent lines).

Why? Are you concerned that water dissolved in the ethanol is going to corrode the aluminum? That's a little hard to imagine. I'm no chemist, but I have a hunch that that the same ionic action that allows alcohol to keep water suspended probably prevents that suspended water from interacting with metal.

In any case, there's a lot of aluminum parts in a car's fuel system that aren't anodized or alodined -- starting with the throttle body and probably the fuel injectors. My Jimmy hasn't had anything more than a fresh set of plugs in the last 10 years, so something must be protecting it. And water rusts steel, but its gas tank doesn't leak.

It's an interesting question, though. Personally, I wouldn't go to the trouble.

 

[airguy]

Actually, I am a chemist, and to a large degree you're right, that the alcohol will stay in solution (most of the time) rather than coming out. There will be times, however, when some water will come out of solution and the water/alcohol combination is more detrimental to the bare aluminum than water/100LL combination would be. It's not a huge impact, since the alchohol percentage is only 10%, but I'm still going to protect against it.

YMMV.

 

[RVbySDI]

Actually, I am a chemist, and to a large degree you're right, that the alcohol will stay in solution (most of the time) rather than coming out. There will be times, however, when some water will come out of solution and the water/alcohol combination is more detrimental to the bare aluminum than water/100LL combination would be. It's not a huge impact, since the alchohol percentage is only 10%, but I'm still going to protect against it.

YMMV.

I do not think there is going to be enough water in any of our fuel supplies to have it come out of solution if ethanol is used in the fuel. There were some threads about a year or so ago concerning ethanol, fuel, water, vapor lock, etc. that had a very good scientific study cited that calculated the amount of water that would be needed in an alcohol/gasoline mixture before that water would come out of solution with the ethanol. It was somewhere around 1 pint of water per tankful of fuel before that water would separate. That is a lot of water in a tankful of gas! I don't think there would be any of us that would see that much water in our fuel tanks unless the plane sat out in a hurricane with the fuel cap missing.

 

[JHines]

2 out of 3

You'll want to eliminate ALL RUBBER ANYTHING in the fuel system, from the filler cap to the engine manifold. Ethanol in mogas will do a number on the rubber, it's the main reason certified aircraft need an STC to convert. Alodine ALL the fuel-wetted aluminum parts in the entire fuel system (don't forget the pick-up tubes and vent lines). Injected engines seem less prone to vapor lock with mogas than carbs due to higher fuel pressures. There are other items to be done as well to make the engine happier, but some are controversial and you'll get opinions on both sides.

My opinion only - worth what you paid for it.

Airguy,

You've identified 2 of 3 common issues I've seen raised relative to ethanol/alcohol in aircraft. The solutions seem pretty straightforward.

What about alcohol retaining a substantial amount of water in the tanks and feed lines and then freezing at altitude?

I'm really interested in building "alcohol-tolerant" and it seems the freezing issue, if it is a real threat, wouldn't have a simple solution as the materials compatibility/vapor lock issues.

 

[airguy]

For the low levels of water that we would normally see dissolved in fuel, it won't be a problem. The dissolved water will have a freezing point significantly depressed below normal, and if you did get cold enough it would freeze out into small crystals which would not coagulate, they would settle out to the bottom of the tank. That does raise the possibility of plugging a fuel filter - but if the level of water was high enough to reach this point anyway, you would have likely caught it during your preflight drain check.

The best solution is to keep fresh seals on your fuel caps - change them at the annual condition inspection. This will prevent rainwater or washwater from entering the tanks, and that will be 99.9% of the water contamination problem licked.

There are many opinions for and against building an aircraft that is ethanol tolerant. There is no shortage of individuals posting on here that will tell you it's not safe and you're going to die, immediately if not sooner, if ethanol ever comes within 200 yards of your aircraft. Make your own decisions for your own reasons. I have and do, and when people try to talk me out of it, I just shrug my shoulders and walk away. Build YOUR airplane the way YOU see fit and don't let the other guys tell you differently. A certain comfort level with experimentation and the subject matter involved is required any time you go off-plan, but I would offer to the table that with all the mogas STC's out there and the increasing number of aircraft running ethanol mogas, E85, and straight ethanol, it is not impossible, it's not even necessarily dangerous if done right - it's just off-plan. Do the research, understand the challenges, and build it according to your comfort level.

I offer only advice, never direction.

Why? Are you concerned that water dissolved in the ethanol is going to corrode the aluminum? That's a little hard to imagine. I'm no chemist, but I have a hunch that that the same ionic action that allows alcohol to keep water suspended probably prevents that suspended water from interacting with metal.

Not so, I'm afraid. If that was the case, there would be no corrosion difference between pure clean water and salt water. The ionic suspension action between the water in the alcohol in the fuel and the salt in the seawater is the same process.