I'm just starting a GP Lancair and have 2 questions.
1) The firewall doesn't appear to be as well glued as I'd like so I figure I'd better check the wings, too. How far out are people stripping the covering and finding problems?
2) On initial balance are people finding it nose or tail heavy and with which engine? How much weight are you having to add to get it balanced?

Al,

I never altered a thing. I went exactly by the book and everything is still in tact after a year of use. I am running a Saito .91 in mine. Have yet to have a problem with anything.

John

I beefed up the firewall joint with some epoxy just for insurance. I did find that I had a nose heavy plane using my OS 61FX. Had to use a larger battery pack and shove it way back in the fuse. My additions to the firewall helped cause the nose heavy condition.

I am at at total loss as to this beefing up the firewall discussion. The Ply is behindfirewall is behind the fiberglass fuse's firewall. Once you install blind nuts and motormount, it can't possibly go anywhere.
I'll bet that the play firewall doesn't even need to be glued to the inside of the fuse. Now, I'm sure it is, but I would certainly see no reason to add even 1 gram of weight in reinforcement.
Think about it. I now a lot of arfers like to beef the firewall on the typical ply-to-balsa type of construction.
When I see discussion of this reinforcement, it makes me wonder if it is a post in an incorrect thread, or the person actually has a Lanier and is dislexic or something, thinking Lancair.
Pllease explain why you would have any need to reinforce the firewall.
Thanks,
Paul

Before I built anything I visualized the firewall from behind. A bead of glue can be seen running around the joint with the exception of about a 3 inch gap on one side. I know the firewall is offset but it makes me nervous that I can't see that it has been glued ALL the way around. If what you are saying is that there is a second former just behind the firewall then that is the piece that is incompletely glued. Or, does this mean that because of the fiberglass construction the plywood former that I am calling the firewall just needs to be tacked in and that the fiberglass will then take the stress? If that is the case then maybe I shouldn't add more glue. And no, I'm not dyslexic -- this is a new GP lancair ARF.

Al,
If you want to add some epoxy in missing areas around the firewall, have at it. Most Lancairs' need tailweight to balance, so adding any weight up front is probably not a good idea. I altered the guts on our latest Lancair (see photo gallery) to move most of the equipment back into the baggage area. You can see pics of the alteration here
http://www.rcuniverse.com/forum/m_80...ictures/tm.htm
At any rate, once the engine mount is...well...mounted, It can't possibly pull out of the plane, which, on a typical wood-constructed arf could have the engine/firewall leave the plane.
I am sure that the firewall is glued to the inside of the fiberglass firewall as I removed the one from our first Lancair (crashed [] ) to use as a drilling template on the new one.
There's glue all over the front face of the ply firewall, not just on the edges.
Didn't mean to accuse you of dislexia in particular, I've seen this topic come up before and it always caused me to wonder.

Paul

I think I understand, now. This is my first venture into fiberglass so I'm still unclear on the concept at times. I take it the consensus is to reinforce the wing but not to worry about the rest of the structure. That nose-heavy problem could be there for me since I'm using a Saito 100T. I had already decided to mount the batteries (radio and glow driver) as far aft as possible and am considering moving the rudder and elevator servos back there as well.

I have two Lancairs. My first one is very near stock and built per the instructions with no major modifications. I am using an OS 91 Surpass II and filled the aluminum spar with lead and she balance nearly perfect.

As far as reinforcing the firewall, I agree with Paul (SDCrashmaster). The plywood firewall is on the inside of the fiberglass. Once you bolt the engine mount to the plywood, the only way to pull it out is to break the fiberglass. An incident that would result in breaking the fiberglass around the firewall will probably be a major crash with damage to other parts of the plane as well. I did not add any glue to the inside of the firewall and don't see a need to do so.

Hi all,

I'm in the process of assembling mine, and I have a question regarding the nose gear. Just trial fitting things, it appears to be too close to the firewall for the nylon nose gear steering arm to turn enough to the left. Are the instructions ok on this or has anyone been forced to modify it?

Thanks!

If you haven't already seen it, there is a review of this plane here on rcuniverse ([link]http://www.rcuniverse.com/magazine/article_display.cfm?article_id=246[/link]) that mentions shimming of the nose gear. I haven't gotten to that point yet, but have found that problem in other kits in the past and intend to mount the gear further forward than in specified.

Shimming the nose gear mount:

I used the stock nose ger on my first Lancair and found the same problem. Instead of shimming, I notched a cut-out in the firewall to allow the spring to rotate freely. In retrospeck, that might have weakened the firewall but not to any great extent. I have not had any problems with this installation. However, the nosewheel is probably the weakest part of this ARF. This gear will easily bend from side to side and backwards (I fly off grass). This may be good for flexibility but it looks bad. Although I am still using the stock equipment on the first Lancair, I installed a Robart nose wheel on my "Partiot" version. Can't comment on how it wroks yet....