Official Black Horse 1724mm Dornier DO335 Pfeil ("Arrow") Thread

[MrSmoothie]

Contemplating counter sinking into the MAS prop hub to allow the prop nut to get a couple more threads for insurance.

I'm no expert (but I know some, haha). But I think your problem goes beyond getting "a couple more threads". Unless I'm not seeing things correctly, your aluminum spinner base plate is sitting on top of the round portion of the motor shaft base (you've enlarged the hole in the spinner base to fit over the hex portion, if I understand correctly). You may have the more square shaped base (rounded corners), but same issue.

This doesn't seem to be enough surface area for the spinner to contact to remain tight, without having the hex shape to engage any more. When I designed my 3D spinners to work with that motor shaft, they took into account the hex as well as the round base portion. These spinners are still working fine, knock on wood -- er, PLA.

I guess you won't know until you try it -- might be worth setting up on a test stand first?

[MrSmoothie]

I'm very much enjoying my Pfeil, even if it isn't the kind of model you bring out every trip -- sort of a "special occasion" model. I'm feeling much more comfortable flying it, and especially landing it. This video is from last weekend. The second flight landed right on the geotex centerline (I swear!). These were the first two flights with the new nose strut, a modified Freewing 80mm A-10 part, with the same Robart scale wheel as before. It has some "give" in the oleo which I think makes a difference. I'm on the hunt for equally nice main strut oleos.

I've been flying with Roaring Top 6s-32c 6250's. But it's finally dawned on me that with two motors sucking off of one lipo, I really should be using a much higher C lipo and have ordered a 65c 6200 -- I have high hopes that this will make a noticeable difference.

https://youtu.be/Ibp1EYkEHUk

[TwistedGrin]

Received my spinners, reamed out the prop to fit the FreeWing Prop shaft adapter. It has about three threads exposed to make contact. It will tighten down....but I am not confident with this. Contemplating counter sinking into the MAS prop hub to allow the prop nut to get a couple more threads for insurance. I am now looking for a huge bit that will do the job.....maybe use a wood bit to dig into the prop hub material?

UPDATE: Looking into flat bottom end mill bit for this .....waiving off from Wood Working flat side bits

TwistedGrin

[tab28682]

Saturday before the cold front blasted through us....Greater Southwest Aero Modelers was probably heat indexed at 109...ambient 101.....could smell the grass drying up and the heat haze was nasty.

TwistedGrin AMA club 1140

I was at the Shreveport Warbirds for Warriors fly in. Just over 100 there, but heat index there with the humidity was about 106.

in any case, worth doing what you can to help keep heat stress down on all parts of an electric power system around here in the summer

[TwistedGrin]

Here is the Texas heat, I always have some extra capacity in my ESCs, whenever possible. It was over 100 at an regional warbird fly in I went to last weekend.

Saturday before the cold front blasted through us....Greater Southwest Aero Modelers was probably heat indexed at 109...ambient 101.....could smell the grass drying up and the heat haze was nasty.

TwistedGrin AMA club 1140

[tab28682]

5055-400s, 16x10x3 props, 6S batteries are a good power train for the Do-335. You could probably get by with 60A ESCs, but you wouldn’t have much margin over peak current draw.

Here is the Texas heat, I always have some extra capacity in my ESCs, whenever possible. It was over 100 at an regional warbird fly in I went to last weekend.

[TwistedGrin]

Quick study on LiPo mAh sizes reveals the following:
Spektrum 22.2V 7000mAh 6S 30C Smart LiPo Battery: IC5 / SPMX70006S30 weight grams = 890g ...the form factor should fit nicely in the forward battery tray with plenty of room for balancing. I am following Oxotonic's lead for assembly and electronics packages....his dual CNHL 3s 30c 8000mAh package should be about 1182grams. He stated room to move those two LiPo's back some for less nose heavy scenario....this "Might" suggest the SPMX70006s30 LiPo will have enough room to adjust for COG most likely forward center of the battery tray. I like the idea of a single LiPo as it simplifies the wiring harness for dual ESC's - less wiring and less weight again. He still has 1000mAh more flight time though!!

TwistedGrin

[TwistedGrin]

I am in...

Going for the following set up:
DX8 Gen 2 Tx
Spektrum 6 channel Rx
Xwave RM400-90 Electronic Retracts
Hitec HS-645MG Ultra Torque Ball Bearing Metal Gear Standard Servos
ZTW 18A BEC / UBEC - or separate isolated Rx battery depending on CG
ZTW Mantis 85A ESC
Flight Line 5055 390Kv Motors
16x10x3 Pull/Push props
6s 45c 5200mAh LiPo

I just finished a nearly two months of assembly of a SeaGull Cessna Skymaster 336...need to get that aircraft maidened and sorted out before starting this assembly

Still looking for some three blade spinners....might have to give TrueTurn the call

https://www.warhistoryonline.com/mil...3LEJ27ZBEWP_XU

TwistedGrin

[Oxotnik]

5055-400s, 16x10x3 props, 6S batteries are a good power train for the Do-335. You could probably get by with 60A ESCs, but you wouldn’t have much margin over peak current draw.

[tab28682]

Started assembling the Do-335 this weekend.

Fairly impressed with the kit. Very good build quality. Some details could be nit picked, but the overall effect is nice.

I like the weathered detailed covering, but would be nice if it were not quite so dark. Ought to look better out in the sunlight.

Powerwise, going with a pair of GForce D5055 400Kv motors and Hobbywing 80 amp ESCs. Master Airscrew 16x10x3 props, might cut down to 15” if needed. Undecided on the ultimate spinner solution so far, but 3D printing is attractive. Servos are a mix of what I have on hand and available. Using the recommended Xwave retracts.

I dismounted the instrument panel so I could mask off the dials and gauges (computer cut vinyl) and anything that is behind glass and paint the rest of the clear panel grey and black.

Not going to go too crazy with extra details. The goal is to get it in the air in a few weeks.

[Twowingtj]

Tony, my plan was to run a std prop on the aft mounted backwards and run the motor backwards, worked great on ralphs DH-2. do you see any problems with that?

Joe

On the DH-2 it wouldn't cause a problem mainly because the prop is basically in the center of the airframe.

On the 335, what you are planning, might be a problem. Alpha indicated that the plane was designed to have contra-rotating props. The front CCW, as viewed from the front and the rear CW as viewed from the front.

Both motor mounts have thrust offset built in for that configuration. If the rear were rotating in the opposite direction, it might amplify or add to the P-factor already acting on the tail surfaces. It may even want to induce a roll tendency to the left, as Oxotik indicated. And there may be other affects that don't come to mind at the moment.

[Oxotnik]

Tony, my plan was to run a std prop on the aft mounted backwards and run the motor backwards, worked great on ralphs DH-2. do you see any problems with that?

Joe

The the prop will be turning in the same direction as the tractor prop, right, and not counter-rotating? I would think that non counter rotating props would probably wouldn't have much a negative effect on yaw (P-factor) in the tractor/pusher config, but would probably give you a very noticeable difference in roll rate to the left versus right.

[paladin]

Tony, my plan was to run a std prop on the aft mounted backwards and run the motor backwards, worked great on ralphs DH-2. do you see any problems with that?

Joe

[TwistedGrin]

TwistedGrin based on the specs for the Admral GP10 motors, they may not handle the Master Airscrew 16x10x3 props on 6S. Most that are flying this bird are using larger lipo packs for both balance and duration of flight. There's a lot of tail aft of the CG.
r
Vextren The specific specs for the props you will use depends on the motors you choose. Keep in mind that the recommended prop range in the motor specs are for two blade props. When going from a 2-blade to a 3-blade, you want to go down one inch in diameter and up one in pitch. So if he motor calls for a 15x6, you would want to use a 14x7 or 8 3-blade prop.

On this bird you will want one normal or tractor prop on the front and a pusher on the rear. Master Airscrew has the best variety of 3-blade props. They are what most of us are using.

While 3-blade props look great from a scale perspective, they aren't as efficient as 2-blade props. They also weigh more. There's also the added expense of custom 3-blade spinners if you go that route. The ones I ordered from Tru-Turn were over $180 for the pair. All good things to consider while outfitting your Do-335.
https://www.masterairscrew.com/collections/3-blade

10:4 Well I have options then....I have two Flight Line 3055 390Kv Motors and 16x10x3 props (Standard/Pusher) combo on hand.....was hoping the Admiral motors would be a little less weight. I still like the 3blade option...but no spinners for this set up.

Not too keen on 2 blade props but have not done my homework for the watt numbers on the recommended Admiral set up.....I sure don't want underpowered aircraft so I usually prefer the penalties of beefing up the power train for grass field operations

TwistedGrin

[Twowingtj]

Alpha let's hope so. Having the opportunity to fly something "out of the ordinary" appeals to many of us. Especially if it fly's well and looks decent.

Keep bringing them to us and we will have to have them.

[Alpha]

Hopefully they last longer than the previous batches!

[tab28682]

I missed out on the first shipment (was working out of town that week and not checking RCG, HS, or MRC), but ordered the Do335 and the retracts today.

Still mulling over motor choices. I have plenty of standard size digital servos.

[Twowingtj]

TwistedGrin based on the specs for the Admral GP10 motors, they may not handle the Master Airscrew 16x10x3 props on 6S. Most that are flying this bird are using larger lipo packs for both balance and duration of flight. There's a lot of tail aft of the CG.

Vextren The specific specs for the props you will use depends on the motors you choose. Keep in mind that the recommended prop range in the motor specs are for two blade props. When going from a 2-blade to a 3-blade, you want to go down one inch in diameter and up one in pitch. So if he motor calls for a 15x6, you would want to use a 14x7 or 8 3-blade prop.

On this bird you will want one normal or tractor prop on the front and a pusher on the rear. Master Airscrew has the best variety of 3-blade props. They are what most of us are using.

While 3-blade props look great from a scale perspective, they aren't as efficient as 2-blade props. They also weigh more. There's also the added expense of custom 3-blade spinners if you go that route. The ones I ordered from Tru-Turn were over $180 for the pair. All good things to consider while outfitting your Do-335.

https://www.masterairscrew.com/collections/3-blade

[Vextren]

Finally got one of these. Coming from the new shipment. If anyone has the specs and links for where to get the 3 blade props and such let me know. If you have mods you have done let me know.

[TwistedGrin]

I am in...

Going for the following set up:
DX8 Gen 2 Tx
Spektrum 6 channel Rx
Xwave RM400-90 Electronic Retracts
Hitec HS-645MG Ultra Torque Ball Bearing Metal Gear Standard Servos
ZTW 18A BEC / UBEC - or separate isolated Rx battery depending on CG
ZTW Mantis 85A ESC
Admiral GP10 5030-400kV motors
16x10x3 Pull/Push props
6s 45c 5200mAh LiPo

TwistedGrin