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Old Apr 16, 2012, 10:11 PM
Balsa Flies Better!
Stamford, CT
Joined Oct 2000
6,761 Posts
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Diels Raiden on the bench...

I still seem to keep toying with the idea of heading to the FAC nats this summer and it dawns on me that most of my stuff is really built for indoor, not outdoor.

I've never built a flying model of a Japanese warbird and having done some reading, the Mitsuibishi Raiden caught my eye. By no means does it have ideal proportions for a rubber ship- a Zero or a Kate (B5N2) would be much better. (I may have to pick up another Diels kit...

Dave Diels has started laser cutting a few of his kit line- including the Raiden, but that was after I had started cutting out the parts- D'Oh!

His designs are very scale like and detailed (he blew up the stab a bit), but there is a bit too much wood for my taste. So I did my standard hack out the formers some, wing ribs, somewhat fewer internals in the stab- but I also added a lot of cross grain bracing on the formers to keep them sturdy. I also added some sheet fill in on the nose, figuring I'd rather have wood, then clay.

Another Diels design trait is to build the wings, cover them, and integrate them into the fuse before its fully stringered. This works very well at making sure the wings are sturdy (no plug in stuff here) and allows for very scale like fillets. Downsides- I've only tried to fly one other Diels airplane rubber powered (the Hun was an RC EDF) and that was a Devastator. What I discovered was that the airplane needed more dihedral. Since the wings were so well integrated- trying to add more would have been a nightmare-so I hung it up (it's now been sold at a charity auction...) I think he uses close to scale dihedral- a lot of WWII airplanes had a surprising amount of dihedral- check out a P-38 frontal shot some time. However, I kept looking at the wing on the Raiden, and decided that it could use a bit more- which I added before covering. Again, this is an ILAR approach.

As the bird sits now- wings and tailfeathers covered, but fuse incomplete- she's 15 grams. Dunno if I'll hit 25 grams, which should be flyable. I'll use my standard Tern 6" prop and either 5/32" or two loops of 3/32" rubber.

Sam
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Old Apr 18, 2012, 05:06 AM
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Yak 52's Avatar
UK
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Looks good Sam. I've heard this one isn't too easy to trim but I doubt it'll trouble you! The extra dihedral might make all the difference... It certainly seems to be the solution on some of the other warbirds (Corsair etc).

Jon
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Old Apr 18, 2012, 08:43 AM
Balsa Flies Better!
Stamford, CT
Joined Oct 2000
6,761 Posts
Hi Jon

I've heard very little about this airplane, and I must admit, I've never seen anybody else's Diels kit flying- of anything! But most of the guys I fly with do their own plans, plus we're flying indoors, so maybe this isn't surprising.

I'm hoping I've put in enough dihedral- if not, it'll be a hangar queen. Besides, I must have given you the wrong impression- I don't think my trimming skills are great- I just hang around some guys who are pretty good- my flying buddies include Tom Nallen and Rich Zapf.

Cheers,

Sam
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Old Apr 19, 2012, 08:04 PM
Balsa Flies Better!
Stamford, CT
Joined Oct 2000
6,761 Posts
For those folks who may be doubting why I think that adding dihedral to this airplane after it's assembled- well, here a couple of shots which should show you how tough it would be.
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Old Apr 20, 2012, 03:01 AM
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Originally Posted by Megowcoupe View Post
I've heard very little about this airplane, and I must admit, I've never seen anybody else's Diels kit flying- of anything!
Sam, it was John Ernst that made the comment, can't remember where but somewhere on the forums he mentioned he'd found it tricky to trim.

It's looking good...


Jon
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Old Apr 23, 2012, 11:58 AM
Balsa Flies Better!
Stamford, CT
Joined Oct 2000
6,761 Posts
Hi Jon

Thanks for the steer to John Ernst's page- some useful reading there...Makes me feel better watching some of those airplanes fly...

One of the grumbles I've got with the kit is the canopy.... I have a hunch that Dave didn't lighten the canopy from the beta kit that John built- mine is at 4 grams! This may not sound like a lot, but the rest of the airframe- covered and doped is 21 grams. (noseblock sans bearing and prop.)

I'm not sure why people say be careful with dope adding weight. I put two coats of 50/50 thinned nitrate on the fuse tissue, and the scale didn't budge (it's only accurate to 1 gram anyhow.)

I've got an idea for the canopy- the windscreen part of the canopy is where you'd really like the molding- it's got a complex shape. However, the hood is pretty simple- looks like a simple curve to it. Hence, I'm going to use the windscreen portion of the canopy, and I'll use some much lighter sheet acetate for the hood. This should save some weight without too much trouble.

Sam
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Old Apr 26, 2012, 09:52 PM
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Sebastopol, Ca
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Quote:
Originally Posted by Megowcoupe View Post
Hi Jon

Thanks for the steer to John Ernst's page- some useful reading there...Makes me feel better watching some of those airplanes fly...

One of the grumbles I've got with the kit is the canopy.... I have a hunch that Dave didn't lighten the canopy from the beta kit that John built- mine is at 4 grams! This may not sound like a lot, but the rest of the airframe- covered and doped is 21 grams. (noseblock sans bearing and prop.)

I'm not sure why people say be careful with dope adding weight. I put two coats of 50/50 thinned nitrate on the fuse tissue, and the scale didn't budge (it's only accurate to 1 gram anyhow.)

I've got an idea for the canopy- the windscreen part of the canopy is where you'd really like the molding- it's got a complex shape. However, the hood is pretty simple- looks like a simple curve to it. Hence, I'm going to use the windscreen portion of the canopy, and I'll use some much lighter sheet acetate for the hood. This should save some weight without too much trouble.

Sam
I have had great success making lighter canopys for kits filling the kit canopy with hobby plaster to make a plug to vacuum form plug. After you make a plug you can form a conopy from extremely thin material.


Also I built the Diels Raiden in Peanut scale and it was one of the only scale planes I could never get to fly consistently. Hopefully in the bigger size it will be easier to trim.
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Old May 08, 2012, 08:46 AM
Balsa Flies Better!
Stamford, CT
Joined Oct 2000
6,761 Posts
I've had my Raiden out for some trimming flights and I think it's getting there, although I wouldn't call this airplane much of a threat in a contest! Wound up being a little porker at 43 grams- how did I go from a svelte 15 gram airframe with the wing covered to 43 grams? Lots of noseweight needed is one part of it....plus the bird needs a fair amount of rubber- I'm using a loop of 1/4" about 2x nose to peg. The rubber is turning a cut down Peck 8" prop (down to 7" give or take) with a different blade shape. Don't want to go to a larger prop- it'll be too hard to trim.

So far after two trimming sessions, I've got the airplane to fly what may be a consistent left/left pattern. Going right is a no/no- I've got a lot of washout on the starboard tip and she'll spiral in. The last trimming session was in the dark, so I only had glimpses of the airplane, but she certainly doesn't have much hang. Also tough to get much climb out of this airplane- a distinction from full scale I'd rather not have. The full scale bird was the fighter most successful against the high flying B-29s. I was able to get a couple of laps on hand winds, so the airplane may be able to hit 30 seconds or so when wound properly.

One other trick I tried- which I think is going to work OK- given that I need a lot of noseweight on this bird, I added a rare earth magnet (rc hatch size) to the firewall, and half a washer to the noseblock with Gorilla snot. This helps keep the noseblock in place when the rubber runs down- probably going to have to do this on a few other airplanes.

Sam

PS- oh yeah, the airplane is balancing about 1/4" in back of the main spar. I've got probably 3-4 degrees of downthrust, and a bit of right thrust too.
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Old May 14, 2012, 04:49 PM
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United States, MA, Waltham
Joined Dec 2001
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Nice looking model. Probably a good thing, though, that you didn't show up and try to fly it on Saturday. Very windy.

A 1/4" loop! Wow, that's a a lot of power for something that small. I don't use that much on my 23 inch Seversky, which I think has a slightly larger prop.

How many posts of yours have I answered without realizing that Megowcoupe=Sam?

I had the same problem with the Seversky that you had with the Devastator. I hinged the rudder with tissue and now it flies well. I also use the rare earth magnet trick on the Seversky. The magnets stick to the heads of small flat head screws so I can adjust the thrust line easily.

Lincoln
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Old May 16, 2012, 10:35 PM
Balsa Flies Better!
Stamford, CT
Joined Oct 2000
6,761 Posts
Hi Linc...

Well, I figured it was you from the get go!

In terms of power...I use a loop of 1/4" on my 30" Bellanca Jr. but I think that airplane weighs 44 grams! The Raiden is no floater, that's for sure....My Seversky had a pretty small prop- that was another airplane that was tough to trim, but at least it was light and had a lot of wing. I remember you pulling the floppy rudder trick on that airplane- I just blew up the stab instead.

Bummer that you guys had too much wind on Saturday- I was out sailing, so the wind was kind of nice....

Dave- sorry I didn't respond to your post sooner. I'm lazy, so making a mold to pull lighter canopies isn't something I'd care to tackle, but more power to you!

I could see the Raiden just being a nightmare as a p-nut. I'm not crazy about p-nuts anyhow, and this one is just not enough wing, and too much fuse- really is tougher in the p-nut range.

Sam
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Old Jun 20, 2012, 06:46 PM
Balsa Flies Better!
Stamford, CT
Joined Oct 2000
6,761 Posts
A few updates...Here's the airplane tarted up a bit more. I've still got to paint the spinner though. Flying weight is 45 grams (the Bellanca I think was closer to 65- not 44 as erroneously reported earlier- or maybe it was 58? dunno...) It's hard to trim- there's a fine line between getting a left hand circle and tightening in- I may have to use some tip weight on the outside tip- but if you try to open the circle up- if the airplane stalls, it breaks right and spirals down. I kept trying to trim it in too much breeze this past Sunday and folded a wing- but this shot is taken after the repair. I hate adding guns- they weakened the leading edge and that's where it broke.

Sam
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Old Jun 22, 2012, 01:46 PM
Balsa Flies Better!
Stamford, CT
Joined Oct 2000
6,761 Posts
Some additional testing last night. No joy- the wing broke again. This airplane is already showing a lot of battle scars for the amount of flight time it's accumulated- I've had to patch a bunch already and some of the decals are blowing apart too.

The problem? At the heart- this airplane has a lousy glide. While gliding biplanes doesn't tell you much often- gliding monoplanes does. My rule of thumb is that if the airplane has a good glide with no prop and rubber on it- you should have a decent flying airplane. This one however, glides like a Hot Kanary with no power- no hang- not much distance. The airplane has a high stall speed- and a lot of drag- not a good combination.

Since the airplane's been unpredictable- my next move was to cut down the prop a bit. I reduced the blade area out to the tips probably by a 1/3rd or so. Since the airplane doesn't stay up when the powers running down anyhow- this should help keep the airplane in the air without bumping up the rubber- I don't want to add more weight to this porker. If that doesn't work- I'll start cutting down the prop diameter too.

I probably won't bring this airplane to Geneseo- I just don't see it being even vaguely competitive in WWII. Might be back to the Hurri- and if I can build it in time- a Midkiff Zero (A6M2 for the Battle of Midway and WWII. Yes, the kit and plans on his site are for the A6M5, but Mike was very good to me and drew me up some wing plans for the earlier version- it's got longer wings so it might fly a bit better. I just don't know if I can have it built in time.

Sam
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Old Jun 25, 2012, 04:20 PM
Balsa Flies Better!
Stamford, CT
Joined Oct 2000
6,761 Posts
Trimming the prop diameter helped- as did adding a little down trim- but on its last flight- about 8 seconds in- a gust caught a wingtip and it spiraled in to the right hard...Really crumpled the wing about midway out- have to add more wood to splint it back together..... Some of the flights before that though showed some promise- nice left hand circles- climbing to about 20 feet or so without a stall. I'm on hand winds for a lot of trimming- the airplane doesn't fit in my stooge.

Sam
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Old Jun 29, 2012, 06:02 PM
Balsa Flies Better!
Stamford, CT
Joined Oct 2000
6,761 Posts
OK- some success today...

The tweaks- probably the same amount of left rudder- it needs a fair amount. Downthrust- might be 4-5 degrees- there's a lot in there. Some washout in both tips- not a lot though, as well as a little bit of washin in the middle of the left panel. Other tweak- right thrust- needed about 3 degrees. There's more downthrust than right thrust in this airplane, but it takes a lot. Stab is nearly flat now- not much elevator trimmed in. The bird also needed some left tip weight- this to keep the turn from opening up in the glide. A right hand glide is a no/no- this airplane is flying left/left.

I've got a decent climb under power and the airplane is easier to launch- I think this is a function of getting rid of some of the up trim- adding more downthrust, and more right thrust. The airplane will climb to 30-40 feet now on hand winds which is OK. I finally had a flight where the motor was largely done and I had a nice walk for retrieval- a promising sign. I've gotten rid of the stall- I think (fingers crossed). What dawned on me was that if the airplane stalled- it'd break right and go into a death spiral.

And in another sign of success- I don't have any repairs to do! The motor occasionally hangs up- that may be a function of not enough lube or hand winding- but that's not really a repair.

There may be hope for this airplane at Geneseo yet...although I've started on a Mike Midkiff Zero....

Sam
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