Official Dynam 1500mm B-26 Marauder Thread

[TiredIronGRB]

Right, they look like they belong on race horses not an aircraft lol

I hadn't thought about it but you are exactly right....I have a whole shelf of those little jockeys ;)

[rifleman_btx]

Haha indeed

[Hardway]

I give them to my 8 year old daughter! They are food for her dinosaur collection.... :P

[rifleman_btx]

Hahaha that's awesome

[xviper]

Maidened my B-26 this morning. Weather was good, winds light. Used 4000mah, 4s Gravity battery pushed as far back as possible, all tail weights as per stock, no stabilizer used. Flew with low rates on ELE (45%) and AIL (70%). High rates (100%) on RUD. Expo: 30% on everything. No ELE compensation on flaps, deployment 3 seconds.
This grass field is quite smooth but very plush. I didn't video the first, maiden flight as I find it distracting. This plane has adequate power for scale flying. It did require a good run to get off the ground, but not unlike my Flightline P-38. By comparison, my FMS 1450mm P-51 (4 cell) and FMS 1700mm Corsair (6 cell) can get off the ground in 1/2 the distance. My personal taste would prefer if this plane was a 5 cell (or equivalent). I flew the bulk of these flights between 3/4 - full throttle. The only time I could fly it at less power (~1/2 throttle) was during a low, slow, full flap fly by, which exhibited very good stability. Turns had to be planned with use of higher throttle and lots of rudder to keep the plane going where it was pointed (ie, to keep the tail from drooping in the turn). Loops had to be planned with a full power shallow dive. Too much ELE and it rolled at the top as others have already indicated. I did a successful loop but it was with lots of speed and gentle application of ELE.
The following video is of my second flight. Note the angle of UP ELE at the beginning, indication that it was nose heavy. A smaller battery might resolved this and make the plane fly better. Rolls were easy on a straight pass with higher throttle. If flown at higher throttle settings, it never displayed any of the "tip stall" tendencies that have been previously discussed by other owners. Landings with full flaps was a non-issue, so don't know how the gear would take a rough surface. All said, this plane is good value for the money and by previous Dynam standards, is a cut above.

[rifleman_btx]

Nice. I still feel mine had something wrong. Mine didn't fly anywhere near that well

[xviper]

Nice. I still feel mine had something wrong. Mine didn't fly anywhere near that well

That's a shame. Perhaps there are some isolated QC issues. There doesn't seem to be too many videos of this plane flying from private owners as yet, so hard to have a visual comparison as to how each of these things fly. (Mine might be the only one. All the others appear to be from Motion, Grayson or Dynam themselves.)

[rifleman_btx]

As far as I know yours is the first. I looked all over the tail section through the gun port and through the top where the tail feathers bolt on. No weights. However it appeared I had to move the batteries considerably farther back in this fuselage than the first one to cg at 65mm, the 5000 is all the way back.

[themudduck]

Good comments - Xviper thanks for the flight report. I have some other models that have tendencies that mirror some of the characteristics of the full-scale plane... for example the F104 with its small wings requires some careful handling, you have to keep the speed up in turns or it will just fall out. Apparently the model Marauder needs to be flown "fast" just like its big brother and flaps are needed at slower speeds - well that seems appropriate. In some ways, I think this is part of the fun of having a scale model and helps builds better flying skills. I am happy that the Marauder is very close to the correct shape - the designers could have lengthened the fuselage or enlarged the tail to make it fly more gently, but I do like that it's scale.

I'm just not completely convinced (yet) that its nose-heavy. The elevator trim may be off due to a slight stab incidence error. (I'm experimenting with that and will report my results after this weekend's adventures).
A nose-heavy plane will have other characteristics which can be observed, such as not wanting to flare during landing (which it does very nicely with flaps) and heading downhill fast when it's inverted. (I don't remember). So far I've had 4 flights, with the 4000mah battery not pushed all the way back. Its sitting where the front strap can grab the front of the battery. That's about a full inch forward of where XViper described his.

I had very similar results as what XViper described. But at high speed, I could induce an instant snap-roll by giving it full elevator. Since it doesn't seem to be really tail-heavy, that snap might be due to high wing-loading - the plane may simply be heavy. Anyway that's what I'm leaning towards. Just my opinion. So I took out my tail weight and I want to try flying it with a smaller battery to see how it does.... With a smaller battery it will less nose heavy, and lighter overall. The balance point will be further back and I'm guessing it will fly better, at least that's what I'm hoping.

[TiredIronGRB]

I think a 3000 battery would be better suited for the B-26, the 4000 seems pretty heavy for it and a 5000 is just asking for trouble.

[themudduck]

I think a 3000 battery would be better suited for the B-26, the 4000 seems pretty heavy for it and a 5000 is just asking for trouble.

Agreed. After a 6 minute flight my 4000 battery was only down to 3.92 volts so a smaller battery should still provide decent flight times.

[ryramZ]

Snap roll sounds like three things.
Tail heavy...
Too much throw....
Uneven throw...

There is a lot of mass forward of cg as compared to our other twins which means the tail has a lot of work or holding up to do.

[rifleman_btx]

Just for grins anyone else weigh your planes, mine came in at 4.5 lbs with the 4000 installed so I appear to be 1/2lb under the manual weight with the 5000 directly on 5lbs. I really wouldn't think those weights equal to a half pound. no way

[rifleman_btx]

They weigh in at 4oz for both together

[OV10]

Just for grins anyone else weigh your planes, mine came in at 4.5 lbs with the 4000 installed so I appear to be 1/2lb under the manual weight with the 5000 directly on 5lbs. I really wouldn't think those weights equal to a half pound. no way

I always weigh the birds to ensure that the weight to electric thrust ratio(watts per lb) is satisfactory. My sweetie always laughs at me when she sees me standing on the bath scale while holding a new bird.

[rifleman_btx]

Heck yeah me too

[ryramZ]

[rifleman_btx]

The MOS for window licking wasn't available in WW2 hence the clouded windows

[CFIT rob]

Outstanding work ryan. Your pilots must be cheech and chong flying the" labrador" run to have it that smokie. Thanks for the left over p38 nomenclature idea,wil make use of mine. Anyone have wingnuts cockpit 3D printed yet? Curious as to fit and cost.

[xviper]

Flew the B-26 back at my home field (very lumpy, bumpy but short grass). In this video, I used a 3300mah, 4s, Eflite battery, which is 86 grams less than the 4000mah one I was using in the last video. I found the amount of ELE trim only changed by 2 clicks less UP for it to fly level. Inverted flight felt no different. I conclude that the UP incident on the elevator is likely a function of the angle of attack of the horizontal tail surface. That little Uvula looking antenna on the underside fell out on one of the lumps after landing. I'll use a magnet to help hold it in. I have to remove it so I can transport it with the retracts up.
You will also notice that it took off in considerably less distance on the short grass field. In fact, it's as good as all my other prop driven warbirds. Did a big loop at full throttle, after a shallow dive and it looked effortless and tracked straight. Landings on full flaps were once again, a non-issue and the gear seems to be able to take a mild bounce or two without worry. As I get more used to it, I don't stress anymore over the tip stall characteristics. Keep the throttle in upper 2/3rds and just enjoy the flight.
There were more people at this field and the B-26 drew a lot of attention.