Hobby King 1875mm B-17G Flying Fortress V2

[quitcherbitchen]

more pictures

[davegee]

Great pics, Quitcherbitchen! Thanks!

davegee

[Elbee]

I took my Heaven Can Wait to the field for a series of runup, taxiing, and just familiarization tests I did get some high speed taxiing in, but the airplane was barely controllable, departed the runway several times and nosed over. On one occasion the #2 prop struck the ground slightly, but it is still not operating and I"ll have to figure what is going on there.
CheersDavegee

Dave,

I had a thought, though I've not tried it.

Could you add a gyro to assist with both take-off yaw control and landing yaw control to avoid the ground looping?

It seems like you have a traction or authority issue with the tail wheel, as well.

Could you change the geometry of the servo to linkage to allow greater throw?

Just thinking out loud here.

A shame to not fly this beauty after all the work.

Best, LB

[davegee]

Dave,

I had a thought, though I've not tried it.

Could you add a gyro to assist with both take-off yaw control and landing yaw control to avoid the ground looping?

It seems like you have a traction or authority issue with the tail wheel, as well.

Could you change the geometry of the servo to linkage to allow greater throw?

Just thinking out loud here.

A shame to not fly this beauty after all the work.

Best, LB

Thanks, Steve. Those are good points. The main sticking point now is one of my motors got damaged when it tipped up on its nose taxiing and had a prop strike yesterday. It was just a slight bump, but that motor is definitely not working. I pulled it out and tried to test it. It seems to rotate ok by hand, but when the prop is on it, there is some resistance that is not normal. On top of that, the coup de grace is that Hobby King only sells just a few replacement items for this airplane, which does Not include motors. So, unless I can score another motor somewhere, which is doubtful, this airplane is already destined as a display piece somewhere.

Good thoughts though. The tailwheel seems to track ok, but any slight wind and it is completely uncontrollable as that big wing weathercocks into the wind. CG is right where it is supposed to be, so I don't think that is an issue. I had the idea of taking it up for the maiden yesterday, but the results of taxi testing up to that point made it an unwise move to try and fly it. I'm pretty sure it would have crashed had I attempted a takeoff in that very slight crosswind. Never had an rc airplane act like that before. If I don't find a suitable home for it, if I get a replacement motor somehow, I might give it a go, although even that is doubtful for me at this point.

Appreciate your comments.

Merry Christmas!

Dave

[Elbee]

Dave,

Merry Christmas to you, too, my friend.

Best, Steve

https://www.amazon.com/Brushless-Outrunner-Multi-Copter-Fixed-Wing-Helicopters/dp/B0D3DSGZGQ?th=1

[F106DeltaDart]

Merry Christmas Dave! Sorry to hear about your maiden attempt. Don’t give up on it yet! It definitely does get tricky on crosswind takeoffs with that big tail, but it behaves fine once it’s in the air. I recommend giving it as much rudder throw as you can. I also threw an AR8360T in mine to smooth out the bumps on windy days, so the AS3X+ was helped a bit as well.

[davegee]

Merry Christmas Dave! Sorry to hear about your maiden attempt. Don’t give up on it yet! It definitely does get tricky on crosswind takeoffs with that big tail, but it behaves fine once it’s in the air. I recommend giving it as much rudder throw as you can. I also threw an AR8360T in mine to smooth out the bumps on windy days, so the AS3X+ was helped a bit as well.

Thanks for the encouragement, F106DD, and Merry Christmas!

I thought I was sunk to fly this thing again as one of the motors broke somehow when the nose tipped over on a low speed taxi test and got a minor prop strike. When I ran the motors up again, that one was stuck, wouldn't move. So, I took it home and tried to breathe some life into it, but no-go. Plus, it looked to me that HobbyKing didn't sell parts like replacement motors. However, perusing the internet I came across Ali Express and found a page where they offered a few parts for sale, including engine motors! I immediately ordered one. Not sure when it will come, but at least I have a chance to try more tests nd possibly get this thing in the air someday.

Question: How do you have your tailwheel steering and rudder wired? I just have a simple Y-harness that connects the rudder and tail wheel steering to the rudder channel. Is there a better way to do that? For instance, what if I put the tail wheel steering on a separate channel but had it slaved to the rudder channel. Maybe I could use the rotary switch to fine tune the tail wheel steering position? I'm wondering if I did that, set a switch to lock the tailwheel into position for takeoff and landing, and just had the rudder working to keep directional control. I don't know how well this would work for a model airplane, but as you well know, most of these bombers and fighters that were tail wheel airplanes locked the tail wheel in position for takeoffs and landings.

Anyway, anything that comes to mind that you could offer from your experience with the B-17 would be most welcome! And thanks for all the great help you have given me up to this point!



Dave

[F106DeltaDart]

Dave, I have my tail wheel set up on a seperate channel and cranked to max throw. Also disables steering when the gear are retracted. That has worked well for me so far. That said, I do typically only fly it on low wind days since it gets bounced around in turbulence and the weather vaning tendency can make taxiing a real pain.

As for motors, I might have spares if you need them. I have the ones that I robbed from the one that I converted to a static model for my brother.

[davegee]

Dave, I have my tail wheel set up on a seperate channel and cranked to max throw. Also disables steering when the gear are retracted. That has worked well for me so far. That said, I do typically only fly it on low wind days since it gets bounced around in turbulence and the weather vaning tendency can make taxiing a real pain.

As for motors, I might have spares if you need them. I have the ones that I robbed from the one that I converted to a static model for my brother.

That all makes sense. I do have an extra channel for the separate tail wheel. How do you disable the tail wheel gear when the gear is retracted? I should know that, but not sure in my mind how to do it. I have a Spektrum DX18 if that makes any difference or help. Do you still have the tailwheel steering tied into the rudder channel somehow? I'm a little fuzzy on that score, like are they tied through a mix or something?

I appreciate the offer of the motors. I was lucky to just come across the Ali website and digging further I found where they sell motors. I don't know how long those will take to ship from China or wherever, but once I have that in hand, I should be back in business.

Thanks!

Davegee

[F106DeltaDart]

I used a mix to tie it to the rudder, then put that mix assigned to the gear switch, so it disables on gear up.

[davegee]

I used a mix to tie it to the rudder, then put that mix assigned to the gear switch, so it disables on gear up.

Good way to go, I like it! Hopefully I can pull off the same thing on mine.

How do you have your rudder set up for throws, are they from the manual or do you have it max throw like you have the tailwheel set up?


Thanks!

Dave

[Grossman56]

Hey guys, busy in the Grossman 56 Hangar!
I think we finally have a working version of the Cheyenne Turret after many iterations.

the only thing left is to design a piece to eliminate the 'block on the fuse and create something that blends the two together a bit better.


I'm liking it
As regards the separate tailwheel channel that DD suggests, sounds like a good idea as I notice that the stock tail wheel is attached to a very unscale like long arm aka the FMS Pitts. So, I under stand assigning a new channel to the rudder stick and keeping the throws to 125%. So a rudder/tail wheel mix ?? I remember watching an interview with the pilot of a real B17 and he was saying that the very seldom if ever use the rudder because she just doesn't need it. Dave's B17 has the FMS retract system where the pin on the retract fits into a 'sturrup" like plastic piece with a separate servo to steer when the gear is down, aka the FMS P51 and P40. So by doing this mix and cranking the throws for the tail wheel, we should be good??

Grossman56
Dangerous Dan)

[jetfool]

Excellent design work Dan. Practice makes perfect.
I am practicing on a few old pilots and learning the processes you posted, even have the wife involved telling me how it should look. (Hopefully see goes back to watching cooking shows upstairs) LOL

[Grossman56]

Just remember, grass ain't green and the sky ain't blue!
Several layers of color will show through and I know that when I say to myself, "That's good enough", I know I'm getting closer, one or two sessions later and I'm there. Besides, you can always start over again, even if you don't wash the paint off, it'll always work out. Dave printed me a big version of the RAF pilot, probably three times larger than the ones we used in our Spitfires. Getting him to print me a head and I'll maybe do another tutorial with it.

Grossman56
(Dangerous Dan)

[jetfool]

Grossman56,
Please do a post on the big guy. I'm still learning how to blend the facial expressions, eyes on mine.
Best Regards, Rex

[Grossman56]

So many projects....
All of us who have tried to design something using Tinker Cad or like programs, know how many wacks at the cat it takes to get it right. Right?

Number one is the original tail turret, called a steeplechase turret for some strange reason and 2, 3 and 4 are the progressions, four being the final. Dave dropped off the transition piece today and it fits perfectly.


I'll have to do some trimming on the spare fuse and fit it in.
Lots of hours of work on the PC enough to drive you as you the ways of achieving what you envision until suddenly THERE IT IS

Grossman56
(Dangerous Dan)

[davegee]

So many projects....
All of us who have tried to design something using Tinker Cad or like programs, know how many wacks at the cat it takes to get it right. Right?

Number one is the original tail turret, called a steeplechase turret for some strange reason and 2, 3 and 4 are the progressions, four being the final. Dave dropped off the transition piece today and it fits perfectly.


I'll have to do some trimming on the spare fuse and fit it in.
Lots of hours of work on the PC enough to drive you as you the ways of achieving what you envision until suddenly THERE IT IS

Grossman56
(Dangerous Dan)

That looks Great, Dan!!

Cheers

davegee

[jetfool]

Davegee,
Here is a photo I found in my The Mighty Eighth book. thought you might see some things that would help.
Best Regards, Rex

[davegee]

Davegee,
Here is a photo I found in my The Mighty Eighth book. thought you might see some things that would help.
Best Regards, Rex

Thanks, Rex. I hadn't seen that before, and every pic is helpful!

Best to your wife and her surgery. My wife has a procedure on Thursday. That could open up a can of worms, so to speak, but we'll deal with it best we can when we get more info.

Take care,

dave

[davegee]

Hey guys, busy in the Grossman 56 Hangar!
I think we finally have a working version of the Cheyenne Turret after many iterations.

the only thing left is to design a piece to eliminate the 'block on the fuse and create something that blends the two together a bit better.


I'm liking it
As regards the separate tailwheel channel that DD suggests, sounds like a good idea as I notice that the stock tail wheel is attached to a very unscale like long arm aka the FMS Pitts. So, I under stand assigning a new channel to the rudder stick and keeping the throws to 125%. So a rudder/tail wheel mix ?? I remember watching an interview with the pilot of a real B17 and he was saying that the very seldom if ever use the rudder because she just doesn't need it. Dave's B17 has the FMS retract system where the pin on the retract fits into a 'sturrup" like plastic piece with a separate servo to steer when the gear is down, aka the FMS P51 and P40. So by doing this mix and cranking the throws for the tail wheel, we should be good??

Grossman56
Dangerous Dan)

Jets with wing-mounted engines are a lot the same way with rudder. The times you REALLY need a rudder are crosswind takeoffs and landings, especially landings, and engine-out operations, especially an Outboard engine (on 4-engine aircraft). Part of our sim training every year in the 757 was an engine failure at V1 out of Eagle County airport in Vail, CO, which is takeoff decision speed just before rotation, and then climbing out on a very complicated and precise departure path on one engine until about 12,000 feet or so. The leg holding full rudder on the good engine side was pretty darned tired by the time you got to a safe altitude to clean up the aircraft. I remember my leg shaking once I was able to take it off the rudder pedal after 5 minutes holding full rudder and manuvering!!

Cheers

Davegee