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skier

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I figured I'd start a new thread to document my progress with the Minicoupe. As I mentioned in another thread, I'm not sure I'll ever fully build this plane. I'm more just dipping my toes in the water to see what it's like to build an aluminum plane from plans. Along the way, I hope to exercise some of my engineering knowledge (or lack thereof) to test and verify the structure.

As my first step, I'm going to try building a short section (1 ft long)of the wing. I had a coworker cut a template of the ribs from some MDF (see below).

RibTemplate1.jpg

I have some aluminum waiting at a relative's house and over Thanksgiving we're going to try bending it over the template. Hopefully I'll have more to report by 11/28.
 

lake_harley

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I'm surprised there haven't been any posts to your thread. Do you have another matching piece of MDF to sandwich the aluminum in between during the bending? If you don't I suspect you'll have some problem getting good, repeatable bends over just one "form". Also,typically a small radius is used on form blocks to allow a relatively sharp but appropriately radiused bend so the aluminum doesn't crack from a "too sharp" bend.

Lynn
 

dcstrng

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Good to see movement on the Minicoupe – in my (non-expert) opinion one of those unsung successes that has been unwarrantedly overshadowed by newer birds, although it remains fully capable. I thought long and hard about one, but the engine I had acquired didn’t seem like the best fit (and I convinced myself I might need two seats), although Ron said it would work just fine. From the plans and from crawling around Ron Dixon’s venerable MC, it is one of the few plans build birds that can make a Zenith kit look complex. Very straightforward, with minimal surprises and/or exotic parts, and comfortably proven in the air – sort of a TT for those who won’t fit in one…

My defunct blog: http://vamutantcruiser.blogspot.com/2012/06/chat-with-ron-dixon.html
 

pwood66889

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Good to see movement on the Minicoupe – in my (non-expert) opinion one of those unsung successes that has been unwarrantedly overshadowed by newer birds, although it remains fully capable. /QUOTE]
Second that as I have examined the plans. Wish I had a completed airframe to apply my thinking to. Would like to see if I could produce one with "Two Axis" controls like my favorite ride.
Percy in SE Bama
 

dcstrng

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Would like to see if I could produce one with "Two Axis" controls like my favorite ride.
Percy in SE Bama
Other than having looked at several, I know very little about the venerable Ercoupe, except that those who have had them pften turn into fanatics -- a good friend of mine and her husband had one of the fabric winged models years ago, and they'd both fly it a lot after work... both had rather high-stress jobs and this was their after-work therapy chasing summer shadows at dusk...

Apparently the Minicoupe cousin is quite strong -- if I recall the story correctly, Ron told of someone who was up doing moderate aerobatics in his, doing tail-slides with no noticeable effect.
 

rbrochey

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Good to see movement on the Minicoupe – in my (non-expert) opinion one of those unsung successes that has been unwarrantedly overshadowed by newer birds, although it remains fully capable. I thought long and hard about one, but the engine I had acquired didn’t seem like the best fit (and I convinced myself I might need two seats), although Ron said it would work just fine. From the plans and from crawling around Ron Dixon’s venerable MC, it is one of the few plans build birds that can make a Zenith kit look complex. Very straightforward, with minimal surprises and/or exotic parts, and comfortably proven in the air – sort of a TT for those who won’t fit in one…


My defunct blog: http://vamutantcruiser.blogspot.com/2012/06/chat-with-ron-dixon.html
Guess the plans for this are no longer available.. ?? I tried to contact Mini Coupe through Ron's website but the email doesn't work...
 

dcstrng

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Ron is no spring chicken and my impression is he isn't one obsessing about things on the net, but I did see he was answering questions over on both the Teenie Two and MiniCoupe sites within the past couple of months so maybe he'll answer once the holiday hubbub... I ordered a set of Teenie Two plans form him around mid-summer, but he used to have a fairly active life outside the airport so he may be off slaying other dragons at the moment...

You might try either of the TT or MC Yahoo sites to see if anyone knows the status -- the TT site is usually more active, but he's generally on either/both when he's around...
 

Kevin N

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I think Ron watches the mini coupe yahoo board but that board is a ghost town unfortunately. I bought mini coupe plans two years ago by contacting him through the yahoo board.
 

skier

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Do you have another matching piece of MDF to sandwich the aluminum in between during the bending? If you don't I suspect you'll have some problem getting good, repeatable bends over just one "form". Also,typically a small radius is used on form blocks to allow a relatively sharp but appropriately radiused bend so the aluminum doesn't crack from a "too sharp" bend.
The coworker that made the templates for me just forgot to include it initially, however, the plans do call for a 1/8" radius. I added that on Friday before bending the aluminum.

Yes, there are matching templates to sandwich the aluminum.

It is one of the few plans build birds that can make a Zenith kit look complex. Very straightforward, with minimal surprises and/or exotic parts, and comfortably proven in the air – sort of a TT for those who won’t fit in one…
Yes, it does appear to be a simple bird and the plans are pretty good. However, as would be expected based on the vintage, they don't come close to as nice as Vans plans (or I would imagine Sonex). I do think they quote significantly <1000 hours to build one from the plans.

Guess the plans for this are no longer available.. ?? I tried to contact Mini Coupe through Ron's website but the email doesn't work...
I just got mine this summer, so I assume they are still available. When I first contacted Ron he was very responsive. Last time I tried contacting him, he was more difficult to reach. Try calling the phone number on the site.
 

skier

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As I alluded to in the post above, I did get to play with my materials this weekend. And I had a blast doing it.

I used a cheap set of pneumatic shears from Harbor Freight to cut the .040 web, and found them very convenient for roughing out the ribs. I ended up just using some cheap pop rivets from Home Depot to join the pieces. For this, there was no reason to use aviation grade hardware.

The templates worked well for bending the ribs. I didn't do a great job cutting out the aluminum for the ribs, so they didn't come out great. I'm considering making a CAD drawing of them and sending them out for quotes to get cut on a waterjet. There's no way I'd want to cut 28 of those by hand. I'd also like to get quotes to put pilot holes in the aluminum angle used for the spars. It would make the hole process much quicker and easier. My guess is it will end up being prohibitively expensive, but I'm hoping I'll be surprised.

The reading I've done makes it sound like I'd probably get lower quotes for waterjetting the ribs if I plan on fluting them rather than cutting the tabs as shown in the plans. It also seems like the ribs provided in the kit (when one was available) used fluted ribs. I'm guessing it was for the same reason, fewer cuts will make it cheaper.

0001.jpg 0002.jpg

IMG_0959.jpg IMG_1028.jpg
 

dcstrng

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As I alluded to in the post above, I did get to play with my materials this weekend. And I had a blast doing it....The reading I've done makes it sound like I'd probably get lower quotes for waterjetting the ribs if I plan on fluting them rather than cutting the tabs as shown in the plans. It also seems like the ribs provided in the kit (when one was available) used fluted ribs. I'm guessing it was for the same reason, fewer cuts will make it cheaper.

When I was planning to build a MC, I also was aimed at followingthe Sonerai motif that eliminates all those taps with a simple/now-conventional bent edge with the usual screw-driver fluting. Recall the MC was designed before many had much confidence in the way wedo things these days… The ribs and thefirewall (as well as the landing gear) are probably the most complex parts inthe whole bird. Remember, this was designed to be a materials kits that couldbe mailed through the post-office (before the days of Fed-Ex or UPS) with the exception of a few extrusions, etc., whichwere to be locally acquired…

I have the Sonex plans and pull them out from time totime whenever I need a serious dose of humility. As simple as the Wisconsinschool-teacher kept things with his Sonerai, he went full-tilt the other wayfor the Sonex, so much to that there are numerous “instructions” out there onjust how to read the plans, let alone build the plane and the proprietary sparcaps, pretty much dictate buy those whether you want to or nor… Planes like the Sonerai, MC, TT, Tailwind, Buttercupand the like are built in a normal shop, scratch-built Sonex are built by folkswho are either highly-skilled (or willing to become that) or dream of investingin CAD-CAM, computerized cutting tables and the like.

Don’t misunderstand, the Sonex is great plane, wellproven and highly regarded , but I’d reserve that for when I win the lotteryand can afford the quick-build d kit and some occasional builder assistance – Idon’t even dream of RVs. I could see buildinga MC or similar with my weekender skills in 1000-1500 hours; Sonex on my skills…oomph…
 

skier

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I'm torn by the simplicity of building this plane. On one hand, I could probably build the whole thing in <5 years, if I decided to pull the trigger. I'd have a proven plane with allegedly good flying characteristics (Ron Dixon compared it to a slow RV-4).

On the other hand, it's still a relatively "normal" aircraft. In other words, it's not the AZ-705 (http://www.homebuiltairplanes.com/forums/showthread.php?t=25641). I think I could have a wing designed and built for testing by the end of next year, if I wanted to go that route. It wouldn't be the lightest wing, or the simplest wing, but it would be a wing of my own design. And it would get me one step closer to having (in my opinion) the coolest looking plane flying (with the possible exception Rutan's Boomerang).

I have the Sonex plans and pull them out from time totime whenever I need a serious dose of humility. As simple as the Wisconsinschool-teacher kept things with his Sonerai, he went full-tilt the other wayfor the Sonex, so much to that there are numerous “instructions” out there onjust how to read the plans, let alone build the plane and the proprietary sparcaps, pretty much dictate buy those whether you want to or nor… Planes like the Sonerai, MC, TT, Tailwind, Buttercupand the like are built in a normal shop, scratch-built Sonex are built by folkswho are either highly-skilled (or willing to become that) or dream of investingin CAD-CAM, computerized cutting tables and the like.
I've never looked at the Sonex plans in any detail. However, I always thought of the Sonex as a relatively simple aircraft. What about the Sonex makes it much more complicated that the Minicoupe?
 

Kevin N

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28 ribs 28 days. One a day and in a month you move on to the next task. I don't think a real airplane can be built cheaper than the mini coupe or teenie 2 with the simple design they are. The mini coupe has the advantage of Continental A65 power which is still reasonable to acquire.
 

Pops

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One time when I had an Ercoupe, I flew a long cross country flight in formation with a VW powered Minicoupe. I was impressed with the ROC and Cruise with the VW engine. Nice little airplane.
 
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cluttonfred

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skier, since the Minicoupe was originally sold as a kit, is there anything in the plans that is difficult to source or leaves you scratching you head because it was done at the factory?
 

skier

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28 ribs 28 days. One a day and in a month you move on to the next task.
I wasn't worried so much about the time it takes to cut the ribs by hand, as much as the quality I would get from doing so. I've never been able to cut a straight line with a pair of scissors, never mind tin snips.

skier, since the Minicoupe was originally sold as a kit, is there anything in the plans that is difficult to source or leaves you scratching you head because it was done at the factory?
Years ago I had bought the "plans" for the Q-1 from the Quickheads site. Unfortunately they were little more than assembly instructions for the kit, so I wondered the same thing before I bought the plans for the Minicoupe.

After recieving the plans and looking them over I had almost the opposite problem. A call to Ron Dixon confirmed that the set of plans he sells is actually 2 sets of plans. The Minicoupe was originally sold as a set of plans, which is how Ron Dixon built his plane. Those are included in the set of plans he sells. Later it was sold as a kit and those plans are also included in Ron's plans.

As a result, the most challenging part of understanding the plans is to not get confused by the two different ways of building it. The two things I've noticed so far is:
1. It appears like the ribs were fluted in the kit vs having the tabs (like I built above) in the plans.
2. The plates used to join the outer wing panels are slightly different shapes on the kit vs the plans.
 

dcstrng

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I've never looked at the Sonex plans in any detail. However, I always thought of the Sonex as a relatively simple aircraft. What about the Sonex makes it much more complicated that the Minicoupe?
Fair question…

The truth is, the Sonex is a fairly straightforward airframe – plus has an active community. But the Sonex plans (compared to a Sonerai) is like the difference between holding a dime-store novel in one hand and Webster’s unabridged in the other. Just a guess, but I suspect the Sonex was planned as a kit from the first so all the rebending of extrusion cutoffs and items to accommodate odd intersection angles and the like would have been done in the kit (stuff easier to do in 4130 and acetylene than 90-deg extrusions). Probably what put me off the most (although not most folks) was the use of proprietary spar caps that appeared to be an outgrowth of his motor glider experience – never coujld figure out a way to duplicate locally… I bought the plans, have even purchased Sonex parts for other efforts, good folks… but never I worked up the courage to start cutting aluminum…

I’d guess the inadequacy is on me – attitude, lack of patience with the intimidating plans and my inadequate skills/discipline. On my skills and life expectancy, the Sonex is a nice kit plane (don’t think the B-model is offered in plans, and I think Sonex is now pure kit anyway). However, the super flying qualities are well known and clearly has a very enthusiastic following – about as much bang for the buck as you can get into an “LSA compliant” bird I’d guess.
 
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