I spent most of last year hanging out in a tent in the middle of the Afghan desert with a bunch of Marines. During my considerable down-time, besides missing my wife and kids and praying for lack of work, I decided to try my hand at converting some 3-views to FFF plans using the only "CAD" program I had available--MSPaint.

Can't remember which rag I saw it in (EDIT: Backyard Flyer, September '08), but one of last year's RC magazines that my wife sent me had an article with a scratchbuilt balsa/ply Me-410 for SPEED 400 motors. I loved the look of that plane and decided to take a shot at a FFF version. I've done about 30 FFF builds so far, but never a twin and always at least starting from someone else's plans. (And I promised myself I wouldn't post until I had a flying prototype. I'm just getting too excited about it and felt like sharing early. )

I'm a slow builder nowadays, but here's what I'm a-thinkin':
43" span
Scorpion 2208-30 (x2, of course)
Tony65x55's monoblock construction technique
KFm3 wing
AUW around 22oz

I'm not going for a hyper-scale look or anything so other than the above points the goals are pretty simple:
1) Make it fly
2) Make it look more or less like an Me-410
3) Finish before my wife realizes I'm back in the basement building planes again.

kendall

Here are the concept images.



***EDIT: Pics of the finished bird, PLANS and VIDEO are in post #6!***

I started with the wing. If anybody sees potential issues please speak up...

My main concern here is the wing being able to take the stress of having the LG out on the nacelles where they belong. The best I could do is to bend the LG wire so that it extends aft through a slot in the nacelle. It's actually PU'd directly under the spar just beneath that 1/8" ply plate you see in the slot for the wing (pic #5). I'm hoping for a little shock-absorbing action from the LG wire too.

The wing with motors and LG installed weighs 12.6oz.

kendall

Now for the fuse. About the only thing I thought was pretty cool was working out the linkage for the rudder. The toothpick porker in the magazine didn't have a rudder. After getting to this point I figured it was probably because the rudder sits up kinda high on the V-stab eliminating a straight shot for the linkage. But I wanted a rudder both for more scale-ish flying and a tailwheel for ground steering.

I removed the pins from a couple of DuBro nylon hinges, enlarged the barrels with a wee Dremel bit and replaced them with a single piece of 0.037" music wire. The wire not only makes the hinge but extends down as the tailwheel linkage as well. Under the H-stab I put a solder/copper-wrap-reinforced hairpin loop in the wire for the rudder control arm in more or less a torque rod type setup.

The fuse weight (less three 9g servos, 2 ESC's and battery) is 2.6oz.

kendall

This is where I am as of today. Test fitting the various major bits. All it really needs are servos and ESC's to be flyable/crashable at this point. I think I'm going to try flight testing the naked blue airframe before I spend several more hours decorating what very well could be destined for scrapdom. I'm liking the way it's turning out though.

kendall

The naked blue airframe is now complete and geared up. Current weight (without paint and battery) is 20.2oz. With a 3s/1300mAh lipo I guess I'm probably looking at an AUW of around 26oz once it's painted. A bit over the goal but then again my initial estimates were without the rudder and LG. That and I have a fair amount of extra wire weight that I could have dealt with had I planned the layout a bit better.

Waiting for crashing weather...

kendall

Finally got around to making another attempt to get the prototype in the air today. Wounld't you know it friggin' FLEW!! Nice too.

Made 5 flights with the three 3s/1350mAh Rhinos I brought to the field with me. The wind was less than ideal, but it worked out okay.

I put a PROOF OF FLIGHT VIDEO in the video forum. Nothing fancy--just the naked blue prototype not crashing. I'll fix that over the next few days. Uh...the "naked blue" part, not the "not crashing" part. I need get started on a sufficiently sinister looking paint job. I'm just all over it.

kendall

EDIT: 3/29/09 -- Airbrushing complete. New pics and PLANS added!

There aren't many examples to choose from to go by since there are only two Me-410's still in existence. This one, 3U+CC, is at the RAF Museum in Cosford, England. There are some discussions online about what the correct markings should be for this plane, but rather than try and sort out the fray I just gave it the markings it wears on display--those of Gruppe II/Zerstörergeschwader 26. See post #1 for the reference profiles.

After taking the pics I realized that I didn't add the rear-facing MG turrets to the aft fuse sides. I'll get those on tonight.

The plans are made with Bill Segraves' ScaleAndTile3 from the jpeg I created in MSPaint. There are always little changes and custom fittings that go on during a build but these represent the best most complete version I have. The only things missing off the plans are the upper and lower aft fuse decks. I find the cosmetics are always better if you just measure and custom fit those after the tailfeather servos are installed.

Also hoping to shoot some more vid with her in uniform, but it rained all day today.

Thanks for looking.

Looks fantastic Kendall!! Can't wait for your maiden report. Welcome home and Thanks for serving!!!

Sterling

That looks great - how much space have you got for the battery and stuff? That's a pretty short nose so the CG could be tricky.

My guess that rudder won't do a lot in the air, which is why the model you saw didn't bother - but your steerable tail wheel will be really useful if you've got a surface smooth enough to take off from.

Originally Posted by RobinBennett

That looks great - how much space have you got for the battery and stuff? That's a pretty short nose so the CG could be tricky....

There's enough room for a 1800mAh sized bat in the nose--say, 5-6oz. I was planning on using a 25C 3s/1300. Also working in my favor there is the fact that the two motors together put about 3.5oz right up at the level of the nose. I'm pretty hopeful.

EDIT: Since you mentioned it, I went ahead an did a test check of the balance point as is thus far. The model is actually nose heavy right now. I suspect I'll able to put the bat right over the CG and use the tailfeather servo placement to do the final balancing. Online calculator says the CG should be 2.5-2.75" back from the LE at the root based on 25-30% MAC.

Originally Posted by RobinBennett

My guess that rudder won't do a lot in the air...

Maybe not for rudder-demanding aerobatics, but it'll be enough to coordinate turns, I think. Besides, I needed some kind of ground steering and I figured as long as I was adding the weight of a tailwheel servo I'd throw on a rudder too. The other thing about the toothpick version is that it had no LG. Hand toss, belly flop landing--no need for steering.

kendall

Holy crap! Should be gone with lighter motors--maybe 2205's. With the counter-rotating GWS 3-blade 9050's I have on hand these motors draw almost 13A/140W each! On what should be a 22-24oz plane that's pushing 200W/lb. Gonna have to prop down. Looking for ~180W total power.

kendall

Nice work Kendall.

J

Realy great job on the wings and nacells. The fuselage looks like it could have a slight twist in it...
But very nice cool subject too.

Pete

HI tuppertn!
Werrrry niccce idea! No worry about the CG cos if u will make nice and strong nose canon the fire hider is the best place for balancing. If i finis with my other projekt maybe i will build one of this.
I will use this drowing for it. I did not shriked them maybe the bigger is better for u. Good luck!
Zsolt
http://images.netbag.hu/20090201/08410888021.JPG
http://images.netbag.hu/20090201/08411625533.JPG
http://images.netbag.hu/20090201/08412114822.JPG
http://images.netbag.hu/20090201/08412826874.JPG

shotibf109: Where does one get detailed plans like that? I'd like some for MIG-3 and P-51D...


tuppertn: awesome wing design, it will same me some foam from sanding in my future projects.


-BK

Hi bkboggy!
I will post to you some! If i can get your mail addres. Please let me know in PM.