ETLB Squawk Forums — Archive

Time has a way of slipping away but about 10 or 12 years ago I built a MiniMAX 1100 with the lighter F1030 wings and tail. With the 277 Rotax I had the plane weighed 246# empty and I was very pleased with that. On a whim, a few months ago, I bought some really nice 1 X 6 Northern White Pine boards with nice, straight and tight grain, and a "starter" supply of birch and mahogany plywood. Lately I had considered a much-modified Watson Windwagon aluminum plane or a Hummel Ultracruiser. I had a strong start on a Ultracruiser years ago but ended up thinking I was going to get away from aviation and sold it.

Well, after a conversation with a good, pilot friend this morning I have once again thought of building another MiniMAX similar to what I built before, or perhaps a HiMAX which would be nice for cooler temps. In our conversation he reminded me of the simplicity of staying Part 103 ultralight legal and re-stated how he enjoyed flying my MiniMAX. He's a instructor and charter pilot but still has some basic roots and enthusiasm for low and slow aviation.

Those who might remember me will recall that I failed a FAA medical 45+ years ago so whatever I build will have to focus on light weight again to make Part 103 ultralight restrictions. I rather enjoyed the challenge the 1st time and would once again focus on building light on my 2nd go-around. This build will use a 2A042 surplus 2-cylinder 4-stroke engine which has been successfully used by a gentleman named Kevin who, if I remember correctly, is from West Virginia.  https://www.youtube.com/watch?v=cj0hdymXfOg   I incorporated some of his weight saving ideas in my first MiniMAX and would follow that recipe again to keep the weight to 254# or less. Not too sure I could do that on a HiMAX though.....that would be a serious challenge.

Anyway, the ETLB forum was a great help in completing my 1st MiniMAX and I'll try to post progress if I decide to pull the trigger on another MiniMAX. I'll have to dust off my wing rib jig, table saw and plans and buy some fresh T88 epoxy. The 12' worktable is still in place in my basement, but could probably use a re-leveling to make things come out right.

Is TEAM MiniMAX still open and operating? I have seen a couple posts expressing frustration and wonder if David is still open to supply a few proprietary things like control cables?

Lynn Winter

You've got the wood, tools, and space.
Post an update tomorrow of what you got done on day one  : )

Last evening, day/night 1, I spent about 2 hours cutting wing rib gussets. I think I have about 20-ish% of them done and have nice patterns for the gussets of all of the locations. Just about to get started again in a few minutes and will keep at it until it's bedtime.

Lynn

Finished up cutting all of the wing rib gussets last night. About 600 of them! I guess I work slow but I'm at about 9.5 hours now, but I trim off all of the "excess" material from the gussets. It's minor, but I'm watching for every ounce of weight savings I can find in building the parts.

Lynn

I was fortunate enough to get contact info for Kevin who built a 2A042 powered MiniMAX as I referred to in my original post. I hope to contact him in the next few days to get his "recipe" for the 2A042/MiniMAX he built that was still within the weight restraints of Part 103 regulations. To me, this in HUGE!

Lynn

Well. if I stop building ribs now the last one (24th) is curing in the jig providing I stick with going an ultralight build. Still somewhat considering going out on a limb to build a side-by-side 2 seat plane and then I'd probably need to build 4 more ribs.

Lynn

Ahh just build 4 more. Mmmm Spare ribs!

I had a few minutes so got looking at my 4' X 12' work table and I'm pleased the lines to lay out the vertical stabilizer and rudder are faint, but still visible on the table top. I'll darken the lines a bit to see them more clearly. I did a quick check of dimensions so at least I don't have to lay it all out again.

Now I need to get some RS stock cut to sizes needed but leaving Monday on an 8 day vacation so work will resume as soon as I'm back.

Lynn

(I was fortunate enough to get contact info for Kevin who built a 2A042 powered MiniMAX as I referred to in my original post. I hope to contact him in the next few days to get his "recipe" for the 2A042/MiniMAX he built that was still within the weight restraints of Part 103 regulations. To me, this in HUGE!

Lynn)

Lynn, I have a 2A042 engine; actually two of them.  Would you mind sharing what you find out from Kevin?  It would be appreciated
Lynn Garner, El Paso TX

(I was fortunate enough to get contact info for Kevin who built a 2A042 powered MiniMAX as I referred to in my original post. I hope to contact him in the next few days to get his "recipe" for the 2A042/MiniMAX he built that was still within the weight restraints of Part 103 regulations. To me, this in HUGE!

Lynn)

Lynn, I have a 2A042 engine; actually two of them.  Would you mind sharing what you find out from Kevin?  It would be appreciated
Lynn Garner, El Paso TX

Sorry to be so slow in responding. I will need to find the notes I made during my conversation with Kevin. He was very open with what he told me that I don't believe he would mind me passing the information along. I'll try to find it in the next couple days.

Lynn

  Looking up specification for 2A042 continental engine. 76.2 x 76.2 bore and stroke and 695cc. i have no idea about the weight. An auto engine which seems comparable is the Geo metro G10 inline 3 cylinder engine.74 x77 bore and stroke and one extra bonus cylinder.A direct drive version was built by Raven rotorcraft in the 90s.the concept was considered viable.the U/L version was listed weighing 118lbs complete.Raven listed their reduction drive weight as 15 lbs.So i think a hand start version could come out at 100 lbs.does this continental engine have any advantage over the stock 85.5 x 69 bore x stroke 800cc 1/2vw engine ?

does this continental engine have any advantage over the stock 85.5 x 69 bore x stroke 800cc 1/2vw engine ?

I wouldn't go so far as to suggest it has any "advantage" over a 1/2 VW. But........it is in the low to mid 70# range when properly prepped, cost is a small fraction of a 1/2 VW, and to me it's an interesting engine, built to be pretty bulletproof and was designed as a 2 cylinder, not modified to be one. Downside is in reality it's probably about 24-26 HP, but that's enough to fly a ultralight legal weight MiniMAX with a 145# pilot.

And....before someone quotes the spec that it's rated at 10 HP, that was a minimum HP in some ridiculous military specified conditions.

Lynn

First of all, I think it's interesting that our first names seem to be the same.  

As pretty typical for me it turns out that I did not make a lot of notes during my conversation with Kevin. but, here's at least part of what I did note or commit to memory.

As I did on my first MiniMAX which was a sort of hybrid between the 1100 and the 1030, I did build wings to the slightly lighter 1030 MiniMAX. Lighter anti-drag braces and compression ribs. Also, I used 1MM ply for the wing leading edge instead of the 1.5M in the plans. Those were changes that Kevin sugggested and I confirmed with David at TEAM. As best as I understood it, Kevin built tapered wingtips in place of the outer "full size" bay at the wingtip. FWIW, I plan to just build a standard 1030 wing rather than doing a tapered wingtip. You can see his tapered wingtips in the YouTube video of "Kevin's 2A042 MiniMAX". Also, the 1030 "light" tail assembly was used by Kevin and on my first build.

I didn't sound like he modified the engine in particular but did suggest a slightly larger 1 1/4" carburetor from an unknown small engine source. I believe the stock '042 carb is 1 1/8" or 1 3/16'. He did talk like he or another 2A042 user tried increasing the compression ratio but didn't see much benefit. He did use a coil of aluminum tube for oil cooling in place of the heavy piping and oil filter assembly. That of course would mean more frequent oil changes without a filter, but a substantial weight saving. He did trim off any extra flanges etc. that aren't needed when stripping the '042 for airplane use.

His engine mount method was the 1/2 VW mount designed by Morry Hummel. Slight changes might have to be made to the width of the "bed" for the '042. There are some existing bolt holes on the front and rear of the engine crankcase to built ears to mount the engine using Lord mounts.

Very early MiniMAX fuselage length is 13' 11 1/2" (from memory) but the original MiniMAX fuselage was a bit shorter (13' 8"?) which would save a small amount of weight.....but, I expect that might make the plane a bit more "twitchy" so I've still not decided if I would want to go that route. Kevin did tell me his fuselage was a bit shorter than current 1100 plans but didn't recall by exactly how much. There were other minor differences in the early 1100 MiniMAX, especially in the cockpit area that could save a bit of weight. I have a partial set of those early plans but don't know if I'd built according to them or not.

That's about all I can remember for now, but I'll post it if I think of more.

Best wishes.

Lynn  

Thanks Lynn.  I started on of mine a while back and Kevins video made me remember how sweet they sound.  I ended up going Rotax 503 (my field elevation is 4100").  Makes me wonder how much power these little military engines actually produce.  lg

I looked in the construction info for the 1030 and the 1100 for the method of cutting the tapered trailing edge pieces for the rudder, elevator and ailerons, but couldn't find what I'm sure I saw somewhere when I built my first MiniMAX. As I recall, if you start with a 3/4" X 1" piece and cut it at a diagonal just right (standing "upright") you end up with 2 pieces that are 3/8" X 1" X 3/32". Does that sound familiar to anyone? Seems it would work out about right if using a table saw blade that cuts about a 1/8" kerf. Before I experiment and waste nice raw stock I thought I'd ask.

Thanks, in advance.

Lynn

I got sidetracked for about a month but am back to building an hour or so most evenings. Working on the tail parts.....light tail version. Have the vertical stabilizer done with the exception of the leading edge wrap and just finished fitting all the pieces for the rudder. Building the light tail is certainly "fiddly" but to me the weight savings justify it. Also got the gear leg frames built and the top and bottom plywood is glued on one and the other is ready for the plywood.

All of the ribs have been done for some time. After finishing the empanage I'm uncertain if I'll build spars and start wing assembly or do the fuselage first but thinking I'll probably get going on the wings.

I mowed the 3,000' grass strip today at the tiny airport where our EAA Chapter meets. I don't know the width for sure but think about 80' or 100' and It takes a l-o-n-g time to make one round trip. There's also a crosswind runway that's pretty short at maybe 600' or 800', but I guess if it's blowing a good crosswind it doesn't take as much distance to stop. We only have a 5' cut zero turn mower so it took about 3 hours but the look of the freshly mowed runway sure is satisfying.

No work on airplane stuff tomorrow....going drag racing with my mild '60s style front engine dragster. We bracket race and the car itself is getting pretty consistent so hopefully the driver can string some good reaction times together. Sure would like to win and have our photo taken at the end of the night!

Lynn

Progress has been slow and spotty at best. If I could ever get past the fiddly light tail construction I think progress would pick up and be more satisfying. Maybe that would get me in the basement building on a regular basis rather than putting off something that's not so much fun.

Lynn

Ive found the only way i get done with a project is if I get the fuselage complete or mostly complete first. having something that looks like a plane sitting there is the motivation to get through the unpleasant, mind numbing, and difficult bits. Keep at it! I used to keep a dry erase board with simple items needing completed on the shop door and wouldnt allow myself to leave unless I had crossed something off!

Chris

It is taking me way too long to make significant progress but I have just a tiny bit to finish up on the horizontal stabilizer/elevator assembly and then I can move on to something less tedious. The last two days I also planned and built the engine mounts for the 2A042 engine I plan to use. The engine will be cradled in a "bed" mount slightly modified for the size of the '042 engine but on the order of what Morry Hummel did for mounting a 1/2 VW on a MiniMAX. I thought of building a 4130 tubing mount off of the firewall but that would add complexity from the standpoint of providing "hard points" on the firewall, the mount construction itself, and the need to lay out, build and mount a cowl so the engine wasn't just hanging on the front of the plane. The "bed" mount will be part of the front of the fuselage somewhat similar to the mount for the Rotax engines.

I'm thinking that once the tail components are finished I can get onto something more fun.

Lynn