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

[Alpha]

downwind3zero Those look good, considering they're from the Spitfire! Points for ingenuity!

Oxotnik If the Tru-Turn spinners work out, I'd love to stock those as an Upgrade.

[MrSmoothie]

I was holding my breath over the new MotionRC "reveal" today -- considering what I've already spent on m Pfeil! I think the OV-10A will be a very popular product for MRC, but one that I can pass on for now (as opposed to my much-wanted-anticipated-predicted DH98 Mosquito, which I'd have had to pre-order no matter what). Many updates to my RCG build log in the last few days -- almost done with the functional construction, so will be starting on cosmetic stuff soon. https://www.rcgroups.com/forums/show...k-Horse-Models

[downwind3zero]

Better than nothing; found the Flightline spitfire 1600mm gear doors to fit pretty well. Printed a couple of clamps for the struts and attached the covers.

[downwind3zero]

Oxotnik Thanks for the update! Also waiting for TruTurn to show up (front spinner).

[Oxotnik]

I contacted Wendy at TruTurn today. She said that my aft spinner has been cut (she thinks) and is waiting to be shipped. They just have to be allowed to get back into the building to do the packing and shipping. I'd try printing one, but my 3D printer is down (plugged hot head); so, I can't even print one to get me by. I'm thinking about doing a bare prop for the aft. I just cringe, though, at the thought of flying it with a horribly wrong spinner. I'm such a dork... :-/

[Twowingtj]

downwind3zero good idea with the vent holes in the rear spinner. One of my concerns with the rear motor was heat as well. When I ordered the tru-turn spinner for the rear, I opted for the lightened backplate in hopes that it would also draw air through.

I intend to make all of the air scoops functional as well. The lower scoop will have a cleanable screen to keep debris out.

[downwind3zero]

I printed 2 spinners in the correct sizes to get ahead of the game and NJ closed all parks and flying fields today - I can't win.

[Oxotnik]

Oxotnik Looks like we might have a bit of a wait for our spinners from Tru-Turn.

This is from their home page "Tru-Turn orders placed on, or after 3/24/20 will be processed by vital offsite staff and held for production and shipment soon after the governmental orders have been lifted. Please be patient as Tru-Turn orders will be filled after production resumes."

You might be OK as I think you ordered just before that date.

Dang! I was wondering what was taking so long. I may have to maiden without the aft spinner afterall. :-/

[downwind3zero]

Didn't like the gaps in the wheel wells so I used the covering from the cutout of the wells to cover the gaps up.

[Twowingtj]

Oxotnik Looks like we might have a bit of a wait for our spinners from Tru-Turn.

This is from their home page "Tru-Turn orders placed on, or after 3/24/20 will be processed by vital offsite staff and held for production and shipment soon after the governmental orders have been lifted. Please be patient as Tru-Turn orders will be filled after production resumes."

You might be OK as I think you ordered just before that date.

[downwind3zero]

Got it. I like the shape of the one your working on, keep up the good work. I'll see what I can come up with.

[MrSmoothie]

Very nice mod! Do you mind sharing the print for the rear spinner? Thanks Chris

Thanks! Right now, I consider the spinners a work in progress -- every time I print a part, I've changed it a little. Also, the base plate is designed specifically to engage the Flightline F4U Corsair 10mm prop hub -- not just the shaft, but also to engage a hex shape and a larger cylindrical base. I'm using that shaft on a Flightline 1600mm motor, same as Oxotnik. In other words, I think it's a little too "specific" to the parts I'm using. Then there's the big thing -- I haven't spun one yet! I have a test setup and I intend to mount one of the motors, intended prop, and after that, add the spinner, and see how it goes.

Unless you buy one of those FW-190 spinners (I think there are more than one out there that might work, but don't know), the front spinner is nearly as distinctive in profile as the rear spinner. I recall that on the RCG thread for the Starmax/Hobbyking 1600mm FW-190, there are links to a company that makes a nice ARF FW-190, similar size, that offered 2- or 3- bladed spinners. Oxo, do you know what company I'm talking about?

[downwind3zero]

Very nice mod! Do you mind sharing the print for the rear spinner? Thanks Chris

[MrSmoothie]

I've been busy working on my Pfeil, and spending time on the kind of stuff I probably wouldn't bother with except for the "stay at home" order (and not living in Canada or other cold-for-months locations). Details are on my RCG build log if you're looking for more information. I'm especially happy that I got the nose gear doors hooked up and working. They always look simple in the end (and not like they took hours to figure out)...

https://youtu.be/G5EwMS52JDU

[paladin]

the front spinner can be purchased here:

https://www.dolphinco.com.au/spinner-3-aluminum-2-blades/

joe

[Creative RC]

I do wonder whether the rear prop should have a higher pitch on account of it receiving high speed air from the front prop. The fellow who was flying 4s in a video reported on his link document lower amps on the rear motor at full throttle. Specifically 57 Amps up front and 45 Amps at the rear. He thought it might be due to a longer power wire for the rear motor, but I don't think that alone would account for a 12 Amp difference.

If the amps were made about equal (without exceeding limits of motors) with a higher pitch prop at the rear, then would it not stand to reason that the overall thrust would be higher or better this way?

[MrSmoothie]

Alpha, I'll chime in here -- once I looked closely, it was clear that the front motor has built in right thrust and the rear motor built in left thrust. The firewalls are angled, and the pre-drilled mounting holes are offset laterally. Finally, both cowls have angled "faces" to correspond to the offset spinners. Glad to hear that you went stock. I assume you put a reverse rotating prop on the back end?

[Alpha]

Mine had its motors bolted directly to the stock factory firewall without any modifications in thrust line. The bird flew straight as an Arrow.

[Oxotnik]

Hey, Alpha, since you're checking in on us, an observation has been made about the thrust lines for the tractor and pusher motors. Can you comment on whether there was an intentional offset of the thrust axes for the fore and aft motors?

[Oxotnik]

I'll throw in another dimension to your [wise] musings, Oxotnik: We should also consider the ampacity of the wire being used. Not only will your system not pull nearly as much current as the battery itself is rated to provide, but even if the system did pull 180A continuous, parts of a Power System run into the bottleneck caused by fusing current.

Industrial batteries (12Ah is getting there!) flown in agricultural drones for example, don't need exotic 50c batteries, because their systems don't pull 500+ amps, and even if they did, the wiring would melt!

Power System design is about optimizing everything in a SYSTEM. Prop, motor, ESC, wire gauge and type, battery ampacity (peak, burst, sustained, average unloaded), etc. In the context of an airplane we're also adding Dimensions, Weight, and CG-ability into the equation. If anything in that system changes, the equation outputs differently.

It is best to consider all factors at once to find the best balance of all factors that meets your target.

Why can't anything just be simple???? LOL

Good points all. Thanks!