Luked

Thanks for the tips. I've only tig welded thicker metal so far for practice. Good to have an idea for what to expect on the thin stuff. Btw, your pedals look very nice.

I just ordered a "stubby" gas lens kit. Hopefully that will help in the tube clusters. Also picked up some .045" ER70s-2. I've just got a make sift welding table for now. It's just a 5/8" steel plate sitting on an old power tool stand. Also got some extra 2% lanthanated 3/32" tungsten. Plan to put some practice time in this weekend.

So far tig seems like less hassle than welding with gas. Pretty much just turn on the argon, flip the switch, and you're welding. Stop, start whenever you feel like it. No problem. What's your range of current settings for .035" wall usually?

Thanks for sharing your progress. I'm trying to get back into my Avid project a little, and just switched from oxy-acetylene to tig. Any tips you've found helpful would be great. Appreciate the pictures too. They are good motivation.

Thanks tcj. I just ordered a second one. It's listed as a Ski-Doo Intake Socket on the ebay listing I found. Part number is 420867408 (one number different from the 503 specific part). I think the reason the part number doesn't match the 503 parts diagram is because the injector tube is in the side instead of the bottom. Like you said, I was planning to pre-mix anyway. My motor didn't even  come with an injector.

Number 29,

Thanks for the prop info. It's always nice to have the benefit of someone else's experience. I was thinking the same thing about the way those gaskets work. Not exactly the smoothest intake path. It would make me feel a little better though if I knew I was using the right part. Thanks for checking.

I'm working on gathering the parts to convert my 503 from single carb to dual. One of the main things I need are the small intake runners for each carb. I saw what looked like the right part on ebay new in box for a lot less than what they sell for from Rotax dealers. Thought I'd take a chance, so I bought one to see if it would work. It bolts up fine, and the carb boot fits, but there is a small bulge in the opening where it bolts to the engine. You can see that the intake port doesn't have this shape. Looking in the exploded view in the Rotax part catalog, It appears to have this bulge too. Does anyone remember seeing this before?

Thanks,

Luke

Just looking at your installation Bandit, and would it be possible to bolt a flat piece of 1/4" aluminum plate to the engine, and have holes in that plate to mount the plate to the motor mount maybe 2" or so further back so you could still have a bump out on the firewall for legroom?  That would move the engine forward, and effect the CG of course, but probably not by to much.  If the 582 has room for a footwell, then that engine must sit further forward as well.  JImChuk

Jim, I could be wrong, but I don't think the 582 is mounted much differently. Looking at my 503, I think it's the fan shroud that ends up on the left side of the plane that causes the most problem. I need to get mine mounted on the plane to see where it ends up.

I hadn't really thought of that. It's probably not an issue for me, since I'm not that tall, but I may want to take a passenger once in a while that is a little taller. I'll have to think about that one. I've been spending most of my time shopping for parts to get the engine running. That's my main goal right now.

Thanks Bandit for the pictures. It's helpful to see a complete installation since there are not many pictures out there. I really like the "Plug and Play" part of this engine. The forced air cooling and built in shrouds make things pretty simple.

Number 29, I'm assuming you are running the B gearbox? what type of Powerfin blades are you using?

Thanks guys. I found the pdf Marcus. It's very helpful.

Hey guys,

Thanks for the advice and help. I wasn't really looking for an engine when this one popped up, so I'm still kind of processing what my plan is. This got me excited about the  project again, and is kind of jump starting the completion schedule. When I formulate a good plan, I'll probably be back with more questions.

Jim, thanks for the prop info. That is one of the first things I will want to figure out. It helps to get feedback from people with firsthand experience. A guy out here at the airport has a Power Fin, and really likes it. I just talked to him, and he suggested calling Power Fin to see what they recommend for my engine.

Buckchop, thanks for the picture. The mount on the Avid is "upside down". I think there was at least one Avid where the builder mounted the engine upright though.

Hey Mark, that would be great. Your plane is actually what kept the idea of doing a 503 in the back of my mind over the years. Look forward to seeing how you have your setup.

Well, I guess it doesn't make too much difference now. I went ahead and bought it. Here is a picture from the CL ad. I hope to start working on getting it mounted in the next few weeks. It's a single carb. I think I will probably change to dual carb though.

Hey Everyone,

It's been a while since I've posted in here, and a while since I've been able to work on my Avid projects. My main project is a model C that I'm pretty much completely rebuilding.

I found a Rotax 503 locally, and I've read that there are a few Avids out there with 503s (Bandit for one). I like the idea of a simple air cooled engine. I understand performance wouldn't be spectacular. I'd be flying out of a 3000' asphault runway. I'm about 160, and plan to mostly haul my kids around for rides. I have a few questions for the 2 stroke Rotax experts though.

1. Could my 582 motor mount be modified to fit the 503?

2. What prop would you recommend. I'd like a ground adjustable, but don't know which brand, what diameter, or how many blades would be best for the 503.

3. Are there any 503 models that I should avoid (I can see that it has 4 plugs in the pictures).

4. Anything else to know before I go look at it?

I plan to get a look in the intake and exhaust ports for scoring. Anything else?

Thanks,

Luke

This made me think of the STOL leading edge kits I've seen people install on certified planes. Here are some examples:

https://www.backcountrypilot.org/forum/added-some-weight-to-the-plane-sportsman-stol-15225

https://www.backcountrypilot.org/forum/horton-sportsman-stol-kit-questions-18023?start=20

Notice the foam ribs they use. One benefit is that the wider foam ribs provide more surface area for the sheet metal leading edge. Just a thought.

Fiberglass. I'm actually working on them right now. They will be very similar to the stock tanks with "zig zag" stiffener indentations. At some point I'll try to get some pictures of them, and also pictures of the stock ones since I have a tank cut open.

KD, it's good to hear you are on the road to recovery. Hopefully you will be back to normal soon. Also glad to hear you are thinking about getting back to flying.

Thanks for sharing about your experience. Your accident happened about the time I was starting to rebuild the wings on my speedwing project. It was a major factor in me deciding to extend the wings to decrease stall speed. I hope you find the right plane to get back into it. Avids and Kitfoxes are still a pretty good option. Good luck.

Does anyone know anything about this engine? It looks like they already have a 7 cylinder, and a 3 cylinder, but the 5 cylinder is new. Maybe a nice size for our planes. The history of new aircraft engine manufacturers surviving is not good, but it's an interesting project.

http://www.vernermotor.com/news.html

What do you guys think about it?

It's basically a copy of the stock speedwing tanks that came in the plane except that it will be made of vinyl ester. The stock tanks have 3 baffles, so that's what I'm planning to do.

Hey, right under it was this:

http://www.ebay.com/itm/ROTAX-912UL-80HP-AIRCRAFT-ENGINE-LSA-EXPERIMENTAL-ULTRALIGHT/252283812939?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20131003132420%26meid%3D8429d261f5d649ba8789b4c043a0a07e%26pid%3D100005%26rk%3D4%26rkt%3D6%26sd%3D252282359667

That's kind of like me. It's still just in my head. I've got about 3 vague ideas floating around in there though. I'm not close enough to worry about it too much yet. I do collect pictures of planes with schemes that I like though. You're at the fun part of the project where you can really see big changes as you progress.

Looking good Tjay. Have you got a paint scheme yet?

Thanks. Did a fair amount when we started our business years ago, but mostly just personal projects since then.

Well, I got a little side tracked lately. I decided to build a new gas tank for my wrecked plane. These are made using vinyl ester resin to provide some resistance to ethanol if I ever happen to get any in my tank. I haven't gotten too far yet, but here are some pictures of what I've got so far (this is for a speedwing profile, so the bottom is not undercambered).

First I laid up a flat sheet of glass for the tank bottom

Here's a form I made to hold the sheet in place

I made a cut for the area where the tank bottom has a bend

Double sided tape holds the sheets in the form for more layups. Stainless tape makes the bend transition mold.

Some cloth and mat connect the two areas together.

Some spar tube was used to mold the spar "pockets"

Here they are popped off the tubes.

Hopefully more progress this weekend.

Nice job Larry. You couldn't have done anything much better on this one. Have fun.