Official Dynam 1500mm B-26 Marauder Thread

[OV10]

Unfortunately that low temp idiosyncrasy of the Dynam etracts has been more real rather than being fake news.

[CFIT rob]

That is indeed troubling. Did they work ok at home after warming up? Do you have stock wheels? I too fly year-round. Hate to keep her grounded from something like that. Mine might be the first variant with skis. Reperpose my skymule skis. B26 mulerauder? B26-SM? Maraudski?

[xviper]

That is indeed troubling. Did they work ok at home after warming up? Do you have stock wheels? I too fly year-round. Hate to keep her grounded from something like that. Mine might be the first variant with skis. Reperpose my skymule skis. B26 mulerauder? B26-SM? Maraudski?

They have always worked in the house where it's warm. Yes, I have the stock wheels. I thought at first that the non-functioning wheel was catching, so I cut some of the plastic to make sure. Unfortunately, they stop working after it's had time in the cold air.
I tried the SkyMule with the skis last winter. Unless the snow is very hard and crusty, the plane sinks the skis into the snow and the plane won't get up enough speed to skim on top. Besides, the props just beat the snow like a blender. The B-26, being a heavier plane, may sink even easier. Ice would be fine.

[themudduck]

Hey there Mad Baron - I promised earlier that I would share the settings I use on my radio for the B26. I'm not saying that these settings are required or perfect, they're just what works for me. A lot of this is personal preference.
The only thing that is particularly important is to limit the elevator throw.

I'm using a DX9.

Travel Sub-trim: 90% on aileron and 60% on elevator, 100% everything else
Dual Rate/Expo - I don't have two different rates, I just use one setting. The expo means that the amount of travel is buffered until you move the stick all the way, this results in smoother flight and I don't have to worry about getting full travel until I really want it
Aileron: 100% rate, 30% expo. I am measuring 1" throw each way (which is probably too much for a lot of guys but I like the model to be responsive when I want it.)
Elevator: 70% rate, 40% expo. I am measuring 3/8" throw each way, at maximum. (using the middle hole on the elevator horn) I do still have a bit of up trim, maybe 1.5mm to fly level.
Rudder: 100% rate, 45% expo. (the expo on the rudder is for smoother steering)
Flap settings: 100% up, 40% mid, -55% down. No elevator mix.
Aileron to Rudder mix: 35% (switchable on/off) - this is so the rudder works with the ailerons. I find the B26 drags its butt through aileron turns, so this is quite helpful and I usually fly with the mix on.


And just because I'm typing I may as well include a list of all the modifications I've done to the model out of the box:
epoxied the wing mount fittings into the fuselage
fixed the wing hatch to be flush (mostly magnet repositioning, but some trimming at the front of the wing saddle to get the wing to lay flat on the back side)
replaced the wheels with "scale" wheels. The nose wheel is slightly larger (a slightly nose-high stance helps with takeoffs on grass, plus it looks more scale)
removed and re-glued the flap hinges (because they were loose)
lowered the LE of the stab by about 1mm and raised the TE of the stab by 2mm
trimmed the center part of the stab so it doesn't hit the rudder
removed and re-glued all of the guns because they were loose or installed poorly
installed TI's bombardier's decal
painted the anti-glare panel and the inside of the cockpit OD, repainted the pilots
painted the bare parts of the flaps that are exposed when deployed
painted the servos
repainted some of the invasion stripes to fix some misalignment of the lines... the lines on the flaps didn't line up (picky, picky)
removed the tail weights, which were loose
tested at 65mm but final balance is at 57mm with a 3600mah battery towards the front of the tray

[rifleman_btx]

Just an idea, I wonder if you could place some hand heaters in the retract pockets to keep them above the magic 60°temp. https://www.walmart.com/ip/Hot-Hands...&wl13=&veh=sem

[xviper]

Just an idea, I wonder if you could place some hand heaters in the retract pockets to keep them above the magic 60°temp. https://www.walmart.com/ip/Hot-Hands...&wl13=&veh=sem

Interesting concept but I think they'd interfere with the full movement of the strut. I'm going to see if the old retracts out of my Nemesis or Pilatus will work.

[Mad Baron]

Hey there Mad Baron - I promised earlier that I would share the settings I use on my radio for the B26. I'm not saying that these settings are required or perfect, they're just what works for me. A lot of this is personal preference.
The only thing that is particularly important is to limit the elevator throw.

I'm using a DX9.

Travel Sub-trim: 90% on aileron and 60% on elevator, 100% everything else
Dual Rate/Expo - I don't have two different rates, I just use one setting. The expo means that the amount of travel is buffered until you move the stick all the way, this results in smoother flight and I don't have to worry about getting full travel until I really want it
Aileron: 100% rate, 30% expo. I am measuring 1" throw each way (which is probably too much for a lot of guys but I like the model to be responsive when I want it.)
Elevator: 70% rate, 40% expo. I am measuring 3/8" throw each way, at maximum. (using the middle hole on the elevator horn) I do still have a bit of up trim, maybe 1.5mm to fly level.
Rudder: 100% rate, 45% expo. (the expo on the rudder is for smoother steering)
Flap settings: 100% up, 40% mid, -55% down. No elevator mix.
Aileron to Rudder mix: 35% (switchable on/off) - this is so the rudder works with the ailerons. I find the B26 drags its butt through aileron turns, so this is quite helpful and I usually fly with the mix on.


And just because I'm typing I may as well include a list of all the modifications I've done to the model out of the box:
epoxied the wing mount fittings into the fuselage
fixed the wing hatch to be flush (mostly magnet repositioning, but some trimming at the front of the wing saddle to get the wing to lay flat on the back side)
replaced the wheels with "scale" wheels. The nose wheel is slightly larger (a slightly nose-high stance helps with takeoffs on grass, plus it looks more scale)
removed and re-glued the flap hinges (because they were loose)
lowered the LE of the stab by about 1mm and raised the TE of the stab by 2mm
trimmed the center part of the stab so it doesn't hit the rudder
removed and re-glued all of the guns because they were loose or installed poorly
installed TI's bombardier's decal
painted the anti-glare panel and the inside of the cockpit OD, repainted the pilots
painted the bare parts of the flaps that are exposed when deployed
painted the servos
repainted some of the invasion stripes to fix some misalignment of the lines... the lines on the flaps didn't line up (picky, picky)
removed the tail weights, which were loose
tested at 65mm but final balance is at 57mm with a 3600mah battery towards the front of the tray

Good info I've got my expo rates close to what you have yours set at. I have performed a lot of the mods and repairs that is listed here on the squawk now I have to figure out how to set up the mix on the aileron to rudder mix yet I got a Gavin 8 channel radio for it and the programing the trans is different than my Futaba. Just 3 more days until the maiden flight!

[themudduck]

Good info I've got my expo rates close to what you have yours set at. I have performed a lot of the mods and repairs that is listed here on the squawk now I have to figure out how to set up the mix on the aileron to rudder mix yet I got a Gavin 8 channel radio for it and the programing the trans is different than my Futaba. Just 3 more days until the maiden flight!

Good luck to you! I'm looking forward to your comments after this weekend!

Despite all the grumbling, I really like the way mine flies. I have some other scale planes that need to be handled carefully (Me110 and P51 that like to screw themselves into the ground on takeoff due to prop torque (so they need a firm hand on the rudder during takeoff), and a P47 that has to be landed absolutely perfectly of it will tip over) and these tendencies just remind me that I'm flying a scale plane and not a trainer and I enjoy the challenge.

We all know that the full-size B-26 had a steep learning curve and required particular attention to avoid disaster, and the fact that the model also needs to be flown correctly just seems appropriate to me, if you know what I mean, the fact that it requires some skill makes it more gratifying in my opinion (although its not so friendly to beginners). Its very sensitive to elevator and it needs flaps at low speed. If you pay attention you should have great results!

[NoDirt!]

Hey guys, I am really close to clicking the buy button on this one but I would like to ask if anyone here is able / willing to 3D print the cockpit, guns and site that WW2 Wing Nut created.

I know I can try GrabCAD but I trust you all a bit more.

If you can do it send me a message or post here please. Thanks!

[ruffneckx1]

I may have missed something along the way but I haven't seen too many finished products from the 3D files.

Woody

[NoDirt!]

I may have missed something along the way but I haven't seen too many finished products from the 3D files.

Woody

Yea, I havent either but think they'd be a nice addition.
Mikey 68 had some made but he sold them.

[Bearcat]

Flew the B-26 again today and once again, retract failure while in the air. First, only one retract came down, then after cycling, none came down. I had to land it in the tall grass. Belly flopped it with no damage. I read in the other forum that Dynam retracts may not work below 60F. I think this may be the key to the whole situation. I was flying near freezing temps. Right out of the warm car, the retracts cycled no problem. About 1/2 way into the flight, I tried the retracts and that's when the problems started. As I got further into the flight and the more it flew through the cold air, none of them worked. This is a real bummer. I like to fly all winter long, so unless I replace these retracts with a suitable non-Dynam gear, this thing is done till next spring.
I think Dynam needs to re-think their choice in retracts and use something from the FMS or Freewing bin. Those things have worked for me to well below freezing temps. No matter how interesting the next Dynam product may be, I will buy it with the notion that the retracts will have to be replaced immediately.

Yeah my A-10 is bad about that once it get below 50 degree so either get use to it or leave the gear down...and I have owned my A-10 for about 5 years now.

[Veltro]

In the last week we've test flown three Dynam B-26s: Bird Dog Special, Klank's Tank, and Rosie O'Brady. All three have the CG set at the third panel line from the leading edge (70mm), and the throws set at 1/2 inch for elevator and 5/8 inch for ailerons, with expo on both. Klank's Tank and Rosie O'Brady have the 1/8 inch horizontal stab shim, while Bird Dog Special has a modified thrust line on both engines. This was done by adding one washer to each of the bottom engine mount attachment points.

We found that you have to include a very small amount of rudder to coordinate the turns or she drags her rear and looks like she is tail heavy when she's not. I'm going to mix in a few degrees of rudder deflection for my next flight.

Here's a clip of Bird Dog Special doing a little "IOE training" the other day:

[rifleman_btx]

So what seemed better the shims or the thrust angle? Interesting ideas :)

[rifleman_btx]

Any word when the next parts shipments will be in?

[themudduck]

Veltro, I agree with the rudder suggestion - I've been using a 35% mix since the beginning and find it very helpful for the same reason.

But 70mm for the CG seems way too far back. There are other specific aerobatic tests you can do to see if the plane is balanced, besides normal flight. I'd like to see your reports on how your planes tests at the 70mm position.

[themudduck]

For example:

Assuming your bird is trimmed so it flies level at a medium-high power setting. Fly into the wind.

1) Drive Bird Dog Special along flat and level and then pull up steeply to a 45-degree climb. Then let go of the sticks.
A tail-heavy plane will continue to pitch up by itself. A nose-heavy plane will pitch down by itself. A neutral-balanced plane will continue the same line.

2) Get some altitude, the fly straight and level, pull up a bit, and then roll inverted. A balanced plane will need a little down-elevator to stay level.
If you need a LOT of down-elevator to stay level, its nose heavy. If you need no down elevator (the plane stays level or actually climbs inverted) then its tail heavy.

3) I don't recommend this test for the B26... but here is something else. Again, assuming your plane is trimmed. Take your plane WAY up and then put it in a steep dive (45-degree down) with the power on. A tail-heavy plane will tend to pitch down further all by itself. A nose-heavy plane will pull out (some). Problem with this test is that you will need to reduce power and pull out at speed, and a tail-heavy B26 is really hard to pull out without snapping. That's why I wouldn't suggest doing this!

At 65-70mm my plane headed up all by itself when I did the first test. So I'm flying at about 57mm. And it still snaps like nobody's business....

Most of us prefer to fly a bit nose-heavy. A true neutral position is really for aerobatic planes, so I'm not saying you should make your plane exactly neutral. I'm only suggesting the tests to find out where the neutral point is....

[Ted7rns]

A Tale of Two B-26 Shims.

We flew two B-26's today one with the Shim on the Horizontal Stabilizer (Klink's Tanks) and the other shim the motors up some, then just trim the elevators (Bird Dog Special). Both flew great and we had some fun today. Thanks for the video Kenny.

Our Squadron is growing, we are up to 4 B-26s.

[Ted7rns]

For example:

Assuming your bird is trimmed so it flies level at a medium-high power setting. Fly into the wind.

1) Drive Bird Dog Special along flat and level and then pull up steeply to a 45-degree climb. Then let go of the sticks.
A tail-heavy plane will continue to pitch up by itself. A nose-heavy plane will pitch down by itself. A neutral-balanced plane will continue the same line.

2) Get some altitude, the fly straight and level, pull up a bit, and then roll inverted. A balanced plane will need a little down-elevator to stay level.
If you need a LOT of down-elevator to stay level, its nose heavy. If you need no down elevator (the plane stays level or actually climbs inverted) then its tail heavy.

3) I don't recommend this test for the B26... but here is something else. Again, assuming your plane is trimmed. Take your plane WAY up and then put it in a steep dive (45-degree down) with the power on. A tail-heavy plane will tend to pitch down further all by itself. A nose-heavy plane will pull out (some). Problem with this test is that you will need to reduce power and pull out at speed, and a tail-heavy B26 is really hard to pull out without snapping. That's why I wouldn't suggest doing this!

At 65-70mm my plane headed up all by itself when I did the first test. So I'm flying at about 57mm. And it still snaps like nobody's business....

Most of us prefer to fly a bit nose-heavy. A true neutral position is really for aerobatic planes, so I'm not saying you should make your plane exactly neutral. I'm only suggesting the tests to find out where the neutral point is....

I don't know if we need to fly it to check if it's nose heavy or not... It seems to fly great with the CG out of the box, we didn't have to add weight (There was no weight in the tail). I don't remember the measurement of the CG, This where Motion RC said it should be.

This where the CG's for us. We pretty much try to fly it scale, like a B-26 should be flown as. ;)

[TiredIronGRB]

Welcome to Hobby Squawk Ted, I think you'll really like it here :)