86" Dewoitine 500

[Martin Irvine]

We have the 2008 "Rally of the Giants" coming to Ottawa in June and I have decided on a new plane to take. :)

The Dewoitine 500/501/510 series of fighters were on the cutting edge of technology when they first flew in 1932, but were quickly outmoded by the next generation with closed cockpits and retractable landing gear. I think they were pretty funky with their large gear and wheel pants.

I'm building it to 86" span, (900sq.in.), with an Actro 24-6 and 10 A123 cells, (about 1Kw). I am hoping to come in at 10lbs, (about 25 oz./sq.ft.) but could go up to 12lb. (30 oz.sq.ft.). I am using an old 69" Flying Models plan as a basis and modifying it, (pretty extensively), according to accurate 3-views.

[N99JH]

Martin

I don't know how far into the building you are but there is a set of plans of around 80" wingspan available from a French source which is a very high quality plans. I have the plans as well as the book shown in your posting. If you are interested - I could make you a copy of the plans for cost+ shipping. I could enlarge it to any size you want while running a copy.

Joshua

[staggerwing]

Cool plane !

[Martin Irvine]

Joshua, I've sent an e-mail. (I couldn't find a plan anywhere)

I have the wing cut from foam. I made it 2" thick at the root as that was the material I had. In retrospect, I should have 3M 77'd two thicknesses together and then I could have used my foam cutting pulley machine. On the other hand it still would have been a chore as the bow I am using is not really large enough. Anyway, I did it by hand and have just a little cleaning up of the cores to do.
I have my wing skins joined so hope to get the landing gear torsion mounts and their ply rib reinforcement in today as well as the joiner/spar slot cut, so that I can bag the balsa skins on tonight.

[Michael in Toronto]

I think "funky" is the right word!

Will you be using a scale size prop? (Look at the size of that thing!!!)

[Martin Irvine]

A very productive day. The glue is setting for the evening and we are going out. I've used Gorilla (polyurethane) glue and have found it works pretty well. I wiped the foam cores with a damp cloth to get the glue to kick faster. The dihedral brace slot is filled with a waxpapered piece of scrap. It comes out when the two halves are glued together and replaced with a deep ply dihedral brace.


Yes, it is a big prop Michael! I'll be using a smaller 14-8 (I think). The spinner is just 2 3/4", unusually small for such a large plane.

Martin

[KOMET 44]

Looking good martin ;) I'd say that vacum pump looks FUNKY :D Keep up the good work.As for the rally of the giants,"Is this a I.M.A.A. Event? Any links?

KOMET44

[Martin Irvine]

http://www.fly-imaa.org/imaa/ralley.html

I've built the fuselage jig so that I can cut one piece bulkheads and keep everything straight while I plank it.

Martin

[msp1957]

Look forward to the end result. Very cool.

MP

[Martin Irvine]

Here is the basic fuselage structure. I used scraps of balsa glued to the tops of the jig to pinch the stingers in place while the bulkheads were clamped in place with cheap dollar store clamps. I spent an afternoon assembling this before gluing anything because this is the basis of a straight fuselage. In retrospect, I could also have made a central square lattice, ala Brian Taylor, but this way gives a large open interior.

Martin

[Greg Smith]

I will follow this thread with interest. I have long been a fan of this design for all the reasons you mention. At your target weight it should be a beautiful flyer.

[msp1957]

Looking good.

MP

[Martin Irvine]

Planking is going pretty well. I cut several sheets of 1/8 X 4 X 48 balsa into 3/8 strips with a 5 degree taper on each side. I set my Dremel table saw to cut at 85 degrees, and swap ends each cut so that each strip has both sides with the angle. (Think about it - it does work) The angle helps keep the edges tight as you plank a round fuselage.
All edge to edge joints are glued with Sig-ment solvent glue, (it sands well), and the planks are glued to the bulkheads with CA.

Martin

[Martin Irvine]

Planking is continuing. The weight is looking good. I had figured on 24 oz. for the finished fuselage, and it is looking more like 20 oz. is possible. Not bad for a fat 50" fuselage.

Martin

[J Villa]

Nice plank job!

[Martin Irvine]

A few more pictures of progress.

Martin

[msp1957]

Update?? :)

[Greg Smith]

Fast and nice work!!

Here's some other finishes to consider, enjoy.

[Martin Irvine]

Thanks Greg. Who is the pilot behind the model?

Back at work this week so things slowed down a lot. Got a bunch of sanding done though.

Martin

[Greg Smith]

Patrick Deslandes, http://mcmodels.free.fr/. The photo is at least ten years old. I contacted Patrick a few years back and he said he did not have any plans. He did say the model was an excellent flyer.

[cmcilwee]

Martin,
That is a great, different subject to model, and will be following with interest, build is coming on very well.
Nice size too.....will have plenty of "precence" in the air. Here"s my 80" IL2...does the Dewoitine have flaps??
Would anyone have a link to that French Plans site that Joshua was talking about?....
Josh...can I drop you an e-mail / P message??

Cliff

[N99JH]

Cliff

Great looking Sturmovick. Here is a link to the D-510 plans:

http://www.mra-magazine.com/index.php?option=com_wrapper&Itemid=8

On the left side click "Plans MRA"

then click on the picture titled "Maquettes Avions R.C.", go to page 3 and there you will see the D-510 plans.

Joshua

[Martin Irvine]

Cliff, did you use retracts on the Sturmovik? If so, what brand?
No, the Dewoitine didn't have flaps. It may have had a 1930's version of flapperons. I will be using 2 separate servos so that would be an option.

Martin

[Martin Irvine]

The fuselage is sanded and ready for glassing. I'll add the cylinder bank fairings and head rest after that. It's a lot easier to fair them in with a "hard" surface to blend into. The large ventral/chin radiator will be a removable component.

Weights in the photo:
Fuselage 434g (15.3oz)
Tail 118g (4.1oz)
Wing 776g (27.3oz)

Total weight: 1328g (46.8oz)

Martin

[747drvr]

Martin,

Beautiful work like usual . I love the planked fuselage and diagonal ribs on the ailerons . Very efficient constuction . Almost a lost art ! What will be the power system ?

How are you going to glass it ? My next glassing job will be with WBPU after using a laquer based sanding sealer over the bare balsa .

Marc

[Martin Irvine]

Thanks Marc.
I realize now how much the flash picks up the lightweight filler on the starboard wing - looks like I troweled it on!!
I'm using an Actro 24-6 on 10 X A123 cells. I picked up the Actro used. It seems to run fine, despite having arrived with a bent prop adapter (!) and having been painted (!!) "to look better in a cowling" >sigh<

I figured on using epoxy with .6 glass. I have a few loose planks where I had to sand a bit more, and epoxy will set them. Do you think you save much work/weight with the WBPU? And why the laquer based sealer first?
Martin

[cmcilwee]

Hi Martin, and Josh....
and thanks for the link....yes I used Century Jet retracts on the IL2...
YTou build is coming on very well....watching with interest

Will be sending for the plan tomorrow..thanks for your help again, great site...some great plans in there!

Cliff

[cmcilwee]

Martin,
I"m interested, how you are going to work the modification to the oleo leg going through the top of the wheel spat?
IE....do you intend to keep it "solid"..or moving into the wing slightly for flexing?

Cliff

[N99JH]

Martin,
I"m interested, how you are going to work the modification to the oleo leg going through the top of the wheel spat?
IE....do you intend to keep it "solid"..or moving into the wing slightly for flexing?

Cliff

Cliff

The French plans from MRA show a detailed design for a spring loaded oleo strut.

Joshua

[747drvr]

Martin,

The sanding sealer is very light and will prevent warping of the wood by the WBPU . I don't know if the WBPU will be lighter but it certainly is less toxic and gooey . This guy explains it best and he does VERY good work !

http://www.tompierce.net/190/html/paint.htm

Marc

[Martin Irvine]

Hi Cliff:

The 500 has the oleo connected to the lower axle inside the wheel pant. I am using 3/16" spring steel for the main strut (from the wing root). The oleo will have a pair of springs, one hard and one soft, riding in brass tubes. At the top, it will mount into a classic torsion bar mount. The idea is that the soft spring will take up the initial weight of the aircraft, and allow it to "hang" in flight. The hard spring will be for the real shock absorbing of the landing. This will be aided by the primary 3/16 wire.

The strut from the lower cowling will be mounted with a 4-40 bolt through a ball-link on the end of the strut. This will allow the strut to move as the gear flexes.

I am looking forward to seeing how the MFA plan deals with this. If I like that design better, I'll make changes.

Martin

[cmcilwee]

I"m with you now....what version are you building?...the D500..as per the color plate in your first post?
The 86" plans from France have been ordered.....and..I"ve got a great video of one of these models flying...if only I can work out how to post a link to it!
It"s a beautiful machine in the air, watching the video has made my mind up!

Cliff

[Ron Williams]

Bumpity bump bump

[Martin Irvine]

I've been away a bit the past two weeks - the worst case of gastroenteritis I have ever experienced so lots of "thinking time" in the "reading room"! - but have got some work done.

I am doing the 500 Cliff because I didn't want to deal with the U/C and I preferred the 500 colour schemes. I have just about got the landing gear finished. I'll post some pictures this week. It took quite a while as in addition to the functional oleo legs, there is a drag strut on each side that has to be able to move and to extend in a heavy landing. There are a total of 8 springs in this U/C and several packages of wheel collars, which I use for spacers and stops. I'm afraid to weigh the total, but as I'm below target on the airframe, (what have I forgotten!!??), it should be OK.

Martin

[Martin Irvine]

I've been waiting for landing gear straps (!) - how likely is it that a hobby shop would run out?:( So I've glassed the basic airframe with .6oz cloth and Pacer epoxy. Total weight increase for cloth and the first coat is 150g - 5 1/4oz. I'm happy! I'll scrape another thinned coat on - perhaps another 2-3 oz.

The straps arrived - got the U/C assembled and mounted. Hmmm..... something is wrong. Double check and I find the mounts are all 1" too far forward !! AAARGGHH!!:(:(

So, the rest of the evening was spent making new mounts. Tomorrow, I steel myself and cut into a perfectly good wing. >sigh<

Martin

[Martin Irvine]

After a couple of days deciding what to do about the U/C screw-up, I cut open the wing, channeled out the foam with a solder gun, and set in new plywood. It's finally finished and I think is going to work out just fine.

I started on the radiator, probably the most distinctive feature of the D500. This will have to be detachable so that I can get the wing off. I'm still figuring how to do this so that is is secure but quick and easy to remove.

Martin

[irish_lord99]

I just found this thread while looking through the "giants" forum. I like the planking on the fuse. It actually reminds me of a canoe I made out of 3/16x1" strips of spruce a long time ago. It was a "woodstrip" canoe, and the planking was laid on a jig in the shape of canoe ribs, then after the outside was fiberglassed the jig came out, the inside was fiberglassed, and you had a rib-less canoe. Kind of a neat idea, but probably too flexible for airframe construction. :D

[Martin Irvine]

It is the inside layer of glass that gave your canoe it's torsional stiffness. It's a little tricky to do it through the wing, motor and cockpit cutouts!! :O

Panking isn't really all that difficult, if you use soft, thick (1/8") wood. It is quite satisfying to see the smooth fuselage shape appear through the sanding dust.

Martin

[irish_lord99]

I bet, yeah, when we pulled the canoe off of the jig, it seemed fine until we flipped it right-side up and then it almost bent in half! :/ The inside fiberglass did help a lot, but it never would have been usable without the gunnels and portage rails. It still wanted to fold without them. Planking does look like it would be a lot of fun, but I seldom go as big as the plane you're working on.

[michaelghammer]

Hi Martin

Your Dewoitine is shaping up nicely. What a lovely model of a distinctive looking plane. I stumbled across the Dewoitine when I got a Bill Gunston book this cristmas that had a picture of the D500 in it. It looked very interesting and I thought it would make a nice scale model. I did the obligatory google search for info and 3-plane views and found your Build thread.

Keep up the good work. I´ll definately be watching your progress.

- Michael Hammer

[Mark Wolf]

Beautiful workmanship, Martin! (as usual!!!) :)

[Dave Lindsey]

Martin
Lurking here in the background.
Impressive (as are all your design/builds)
Looking forward to seeing it "up close and personal".
See you in June if not before.
Dave

[msp1957]

Any new pics??

MP

[Martin Irvine]

I've got the landing gear sorted out at last and will post a photo of the whole thing assembled soon. (Strange, but I can't always get the dining room table for photo shots!). The fin is attached and the mechanics of the tail skid are completed.
I now have the two cylinder fairings completed and glassed. I am looking forward to getting the fuselage primed. I like the auto putty for its ease of use and sandability but it looks pretty ugly. The sides of the fairing are 1/64" ply with openings for the exhaust stubs cut. Block balsa finished off the front and rear of the fairings.

***IMPORTANT SAFETY NOTE*** (Darwin Award material!)
The tops of the fairings required a tight curve to be bent in the balsa sheeting. I wanted to use 3/32" balsa so needed to soak the balsa in ammonia. Of course, I'm in a hurry so I wrapped it around a 1" dowel, rubber banded it snug and put the whole thing into the microwave. I have done this before so figured on 5min. I checked it about halfway through and things were drying nicely, (a little steam too). I put it back in the microwave but when I came back it was smelling a little burnt. Hmmm... the steam was blowing out the ends of the dowel so I figure it must be done. Once I got it out, (ouch!! - hot, hot!!), I realized it was SMOKE! The dowel was burning from the inside out. It was getting thicker and thicker as I ran to the back door with it. I fired it into a snow bank and everything was OK after 15 min.
So, I'll use the microwave again, but a little more carefully.

Martin

[vonJaerschky]

That sure looks good Martin. Thanks for the safety story. Your story reminds me of Wiley Coyote or something like that running around with a stick of dynamite before it explodes.

[kimhey]

Great Martin!

A very nice build so far (so nice to see a balsa/wood-project)...I am sure the result will be awesome!!

[Martin Irvine]

Well, here are a few photos of the assembled model. I finally have the U/C sorted out. I am sanding the glass now - it doesn't really take all that long, it's just about my least favourite activity!

Soon it will be primer time and this ugly mess will look a lot better.

Martin

[Martin Irvine]

Sand, putty, sand, prime, putty, sand, prime.................>sigh<

I am getting there.

Martin

[Dave Lindsey]

Looking real good Martin!!!

Dave

[Greg Smith]

It does look good. That cowl is one of the trickiest parts of the D500 look to get right but is important to creating the overall appearance of the aircraft. You're doing great, don't rush it.

[Martin Irvine]

Time for an update.

I have put on 1/64" chart tape (ThunderboltRC) to define the panel lines, (from my 3-view). A layer of primer is applied, sanded off with 600 wet or dry, (used wet),and then the tape is removed. This leaves a good panel line that will survive a thin coat of colour without being obscured.

The rivet lines are from Mick Reeves. They are narrow tapes with rivet circles. The tapes are applied, primer is brushed on and then the tape is removed, leaving a pretty good line of rivets.

Next the dots that were left on the backing strips have a strip of tape put on them and they are pulled off the backing tape and can be applied. These are rubbed down and will be painted. This way you get two sets of rivets for the price of one.

This is taking a while. The wing is 86" long and there is a chord wise rivet line every 1 1/4", upper AND lower surfaces!

Martin

[Martin Irvine]

The rivets are finally done. I estimate there are about 9,000. I'm looking forward to spraying paint.

I found that the stick on strips and the dots take quite a while. Certainly I got faster as the job progressed, but I was a little disappointed at the time required. The dots rarely came off on the tape strips perfectly. Most strips required "patching" - going back to fill in one or two, (or more) that the tape didn't pick up. Not a lot of time but it all added up. On the other hand, the results are very good and the spacing is very consistent. If you don't think the RC56 filled hypo is for you, this is a pretty good alternative.

Martin

[vonJaerschky]

Those rivets and panels look fantastic Martin. She's going to be a beauty. Only 9,000 rivets? That certainly would have taken a while with the hypdermic and glue! I wish I could see it in person.

[Dave Lindsey]

You've got a lot more patience than I have Martin.
Looking forward to seeing it in June
Dave

[Martin Irvine]

Hi dave:

I'm not sure if you were aware, but our E-Fly is the week AFTER the usual date, i.e. on the 5/6 July.

Martin

[Dave Lindsey]

Martin
No I wasn't. I've re-marked the calendar.
Thanks

Dave

[Martin Irvine]

All the surface detail is finished and two coats of Krylon Silver applied. I took it to the EMFSO AGM today. This was the first time I've seen all the bits attached.

[Grumpy Monkey]

Martin,
Wow, nice job, she sure is a looker!

Warren

[Ron Williams]

Bump

[Sanka]

Nice plane. Awesome build..

Any progres??

[Martin Irvine]

Yes, all painting is done, (that was an event) and national markings, (roundels) are complete. I am frantically trying to get it finished for next weekend - BIG event in Ottawa - but life conspires against me! I have this weekend to install radio and maybe even test fly by Sunday. I'll try to post some pictures in the next couple of days.

Martin

[Ron Williams]

Martin -

Please don't rush it. Take all the time you need and bring old reliables to Ottawa. By all means, bring it but don't feel you have to fly it until you're really ready. I cringe when I think of all those rivets being rushed into the air. Life does not conspire against you - put your head back on straight and think of what your frame of mind might be next month if you rekit that lovely thing.

[N99JH]

Any news? I have not seen any postings in awhile, very curious to see the model finished.
Joshua

[Martin Irvine]

Okay!! It's been a while - and a building slump for much of it :(

I spent yesterday cleaning up the landing gear to make sure it slides smoothly. I've assembled it all and taken a few pictures. Hope to have more soon.

Martin

[Martin Irvine]

Nearing flight ready. I have to fit balancing taps to the battery pack, and then the rest is cosmetic - not needed for flight.

Martin

[N99JH]

Very nice Martin. Keep up the good work and let's see her fly. Congrats.
Joshua

[Martin Irvine]

Slow but steady progress. What a pain to move something this big around the shop!

Martin

[N99JH]

Do you have a good estimate of all up weight? What size prop are you planning on using? How much flying time you expect on 10S1P A123 pack?
Joshua

[Martin Irvine]

Hi Joshua:
I think weight will be around 10 lb. The fuselage turned out lighter than I had anticipated, (always a first!).
I think I tested the motor on a 14 X 10 prop and it drew about 35A (from memory). I am anticipating 6 or 7 minutes flight time but recharging will be fast.

Martin

Martin

[Martin Irvine]

Well, I am readying it for test flying but have hit a snag. I have the CG that was on the Flying Models plan and the one on the MRA plan Joshua sent me. Interesting that they differ by 1"(!), when scaled to my size. Using the (more forward) FM position and a pair of "precision calibrated" fingers, I need a pound, (yep, 16oz.) to balance. AARRGG!!! Curse that light and efficient Actro!

So, the next step is to take a long look at the CG, do some calculations, see what can be moved forward, (Rx battery is one), and see how much room is available in the nose. It is where any dead weight should go, but it's pretty tight in there.

All in all, a little depressing, but not insurmountable.

And the weather today is beautiful and nearly windless. -sigh-

Martin

[staggerwing]

Very cool plane--gear looks kinda delicate ?

[Martin Irvine]

The main wire that you can see is 3/16 and the drag wire is 5/32. The oleo is about 3/8".

I used similar with a 12lb PZL, (my avatar) and it held up to some heavy arrivals.

Martin

[Martin Irvine]

IT FLIES!! :D :D
I got the Dewoitine ready for the 15th Annual Kingston FunFly and we got the test flights done, adjustments made and all seems good.

I was a bag of nerves all day waiting for the considerable cross wind to drop or swing. Eventually it did drop enough that I felt comfortable enough. I'm using a new DX7 2.4 radio, and I have never been any good programming a computer radio. Fortunately, Rolly Seimonsen, who is our club radio expert and test pilot was there to race through screens clicking away and everything I had puzzled over through a couple of battery charges was sorted out in less than 5 minutes!

I had moved the 26oz. motor pack forward 3" and stuck the radio pack under it so the CG seemed OK at 25% of the MAC. Generally the test flight seemed pretty good. The motor needed some right side thrust and a second flight by Keith Shaw confirmed this.

Today with the side thrust added, I flew it for the first time. Take-off is dead easy - full up, advance the throttle easing the elevator and she's away at 2/3 throttle! I found the ailerons quite sensitive around neutral but reasonable at full throw. The roll rate is just right for me, about 2 per 3 seconds. Loops are straight and large with the power available - 33A on 10XA123 with an APC 13X8 prop (Actro 25-6). The difference between 2/3 and full throttle seems rather small - room for prop experimentation.

Landing is a little different for a guy who usually flies biplanes!. The first two attempts resulted in go rounds - this is a sleeker plane than I usually fly, but the third attempt got it down safely and smoothly and I taxied back to the pits. 7 minutes of flying needed just 1500mah to recharge, meaning that 10 minute flights are quite reasonable.

I am very happy with how it flies. (Keith said it reminded him of an AstroHog!) I need to remove some of the right thrust I added and re-fair the nose to match the side thrust. :mad:

Now I have to add the scale details - wing registration letters, fuselage squadron insignia, rudder numbers, pilot, wind screen, exhaust stubs, radiator shutters, wheel pants and landing gear strut fairings. Lots to do yet but the basic airframe is confirmed so I can get in practice before MidAmerica in two weeks.

Here are some photos (apologies for the limited quality - it's a point and shoot).

Martin

[vonJaerschky]

Congratulations Martin! Great job on a unique subject. I love the last photo; I wish I was there at the old stompin' grounds for the event. Nice to see Keith overseeing you over your shoulder!

[mistairjoe]

But Messier!!! Where iz ze pilote avec le scarf i ask you??? Quel dommage? Otherwise it is quiet nice i say.Joe

[Martin Irvine]

Thanks Frank, Joe.

Yes, Keith does have a distinctive profile!
And the pilot,( le Comte de Sanyo - he is very old!) got bumped off the morning of the test flight and forgotten at home.

Martin

[Dave Lindsey]

While I missed its maiden and subsequent flight on Sat., I was fortunate enough to catch its third flight on Sun.
This is one impressive bird both on the ground and in the air, and will be even more so when the final detailing is done!
Great Job Martin!!

Dave

[Martin Irvine]

Thanks Dave. Glad you were able to make it out on the weekend.

Martin

[Mark Wolf]

Beautiful! Can't wait to see it! :)