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Thrust Angle

fliteadmin

Administrator
Staff member
Admin
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#1


Thrust angle is a very important and very overlooked element of RC flight. Chad and Josh go over some of the more common thrust angle setups and show what to look for when adjusting thrust angle.

thrust angle - 1.jpg

With the E-flite Taylorcraft 450 ARF as an example, there is a slight right and slight downward thrust angle on the prop.


thrust angle - 4.jpg thrust angle - 9.jpg


This right thrust angle will compensate for the motors torque and because the thrust line is below the tail and the wing this rc airplane. The downward thrust angle will compensate for the planes upward pull.

thrust angle -2.jpg

Seafury Funfighter has an extreme right thrust and this is to compensate for the small size of the plane and the torque of the motor.

thrust angle - 3.jpg


The Bixler 2 features a thrust angle which is angled up. Because this is a a pusher plane and the motor is mounted above the the center line of the airplane, the thrust angle is upward.


Also, because the motor is mounted close to the airplanes CG it will cause the thrust angle to be more dramatic as well.



thrust angle - 10.jpg

Our Fowl Flyer was a good example of not having the thrust angle correct for a pusher plane. At full throttle the plane would pull up and when Josh would let off the throttle, the scratch built turkey plane would glide straight and smooth.




thrust angle - 6.jpg

Chad's custom experimental designed "Arrow to the Knee" slow stick pusher plane is setup with heavy-duty armature wire that allows to adjust thrust angle and test out the best setup. This is a great idea for scratch builds and custom designs.


thrust angle - 5.jpg


But don't let thrust angle overwhelm you, it's always the safest to start with a neutral thrust angle. All of ourswappable fuselage planes feature neutral thrust angle and there's an episode on mixing if you'd like to adjust your plane without worry of adjusting thrust angle.

thrust angle - 7.jpg thrust angle - 8.jpg



For more information on the airplanes and articles mentioned in this Fast Tip:
E-flite Taylorcraft 450 ARF
The Bixler 2
Seafury Funfighter
Fowl Flyer - Turkey Plane
Scratch Built - Swappable fuselage Series
Throttle Mixing
 

Speedbump

Junior Member
#2
This was a really good segment.
I just got done adding some washers to remove some of the right thrust on the HK DR1...never seen a plane with a clockwise spinning prop want to turn right before. Anyway, very useful information.
 
#3
For a dedicated wood pwr pod for FT Mustang or Spitfire what angle R & Down?

I know you want to say it's different for diff planes n pwr systems, but to put numbers to a specific and popular subset, namely FT Mustang and FT Spitfire.

If I want to build a wood ( lite-ply 1g/sq inch ) power pod JUST for FT Mustang, Don't want to use washers, Don't want to use in-flight trim either, you guys must know what the numbers are that makes this plane fly straight.

Using 22mm motors like the "Beef" 2217/7turn/1300kv on 3s w/ gws9x5dd or apc9x4.5e

What angles Right and Down, would you use to get this right? I am going to cut the wood pwr pod frame down at the 8oclock position to give this, then glue the 1/4" hard ply plate to the front and drill extra cooling holes.
The 1/4" ply because Great Planes 6/32 blind nuts will be installed in plate, I like to trade around the motors and try them all: Beef 2217/1300kv, Cobra 2217/1550kv, and Suppo 2217/950kv.

This plate is so strong, 3 extra large cooling holes can be cut in.

My guess would be since if you look at the pic of the Hobby King Seafury Funflyer 600mm 2825-1950kv (can dimensions on this motor, not stator) AUW 305g 10.6oz wingspan 24inch it shows 6.5 degrees, maybe for this case

for this case my guess is 5 degrees Right & 5 degrees down

What do yall know? You have had and flown and experimented with the FT Mustang and FT Spitfire a lot.

If you never measured it in degrees, well then what about if your pod is built for zero degrees like you say, what does the stack of washers you put at 2oclock measure (and 10oclock and 4oclock)???
8oclock would probably be touching the firewall plate.

Right thrust angle powerful motor - question pic.jpg
Thank you, Leonard.
 
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TEAJR66

Flite is good
Mentor
#4
Professor, the pods are built with neutral trust angles. The airframe that receives the pod has the thrust angle. Hence the "C" fold at the front of some planes that gives you the down thrust.

If you want to build thrust angle into the pod, 3 degrees is a good starting point. Again, each airframe will require a little tweaking.

Keep in mind that right thrust requirements can change with prop size changes. If a 6" pitch speed prop has a lot of torque roll on throttle changes, try a 4" pitch speed, or say 4.5 to a 3.8.

A lot of torque roll is reduced as the airplane builds up speed and establishes air flow. If take off is the only time when torque roll is a major issue, try longer roll outs, building speed gradually.
 
#5
Hi, sorry I even mentioned the Flite Test example in the video, seeing your response, but, thank you, just the same.

No my "DEDICATED WOOD POWER POD WILL BE FOR THE FT MUSTANG USING 9 OR 10 INCH PROPS" gws 9x5 dd or apc 9x4.5 with a "BEEF" 2217 motor and I am quite sure that, by now, a lot of people have built and flown the FT Mustang and know what makes it fly straight. No, I'm just asking something simple you have already played with and fiddled with and adjusted to make these fly straight. I might just go with 5R and 5Down if nobody has anything

Thank you tho

Leonard
 
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#6
Custom Mustang Wood Pwr Pod Beef2217 w/ gws9x5 3degR, 2 degDown, is this good?

Listing specifics here, this is a specific wood power pod for a specific type plane and I don't want to use washers, I want it dialed in just right, flat on the firewall, figure I'm always gonna have a FT Mustang, maybe later this might see use in a Stuka or Spitfire, they all need a similar amount of Right thrust correction, maybe a little down and I thought I would just ballpark this in there so that most all of these fly straight. and it's bound to be pretty much the same using the same pwr system and prop and like a 39" dtfb ft warbird

Have yall seen, I don't know whose spitfire video, guy throws it and it whips Left real hard and fast like it could really do with that Right thrust correction, so I did some figures for 3deg R and 2 deg down, this is conservative BUT I have not heard from anyone, nobody has really posted anything, and I never see anything quoted for anything of typical size/weight with a certain power system like your own ft mustang with the beef motor and a 9x5 prop?????????????????????????????

If you built your pwr pod for your ft mustang square and don't know the angle, could you at least post measurement of the height you raised the motor at the 2oclock to correct, do you use about an equal amt of right and down thrust 3R and 3Down or 4R and 4Down? or more tell me your x-mount dimension if you post, ok?

Did some figures you might find interesting for calculating motor offset amount to 2oclock it's about 1/8"not that much and the bottom L corner to achieve 3R 2D comes to cutting back this corner 2.7/16 of an inch or .16875, yah I know that may look funny but when you want to measure it, you can eyeball seven tenths of a sixteenth pretty good and when you want that angle or anything pretty close, well you can cut it close, just 2.7 of those little marks, right?!

Ever heard of SOH CAH TOA soak a toe, mnemonic to help you remember the trig relations?
Tan of angle = opp side length / adj side length Tan ang = O/A then rearrange to get the unknown by itself like I did on the paper

I use those blind nuts because I like to trade around the motors, and like these w/ 6/32 allen head screws better and this tough 1/4" ply, you can cut out 4 big holes for cooling in it and it will still hold your motor real good.

If anybody wants to reply and say it needs more, I just did the figs tonight, will probably build 2 pwr pods tomorrow, one for the BEEF and one for the Suppo 2814 1400kv to use with a apc 9x6e
I just have not done as much building and flying with power as yall except with gliders a long time ago.

Tell me if you know it needs more give us a shout, post it!

FT WOOD POWER POD for 2217 Beef with gws 9x5 dd prop 3Right 2 Down.jpg

Oh hey, I have already heard/read many places about just flight testing to see if it pulls Left then add washers and so am already much much aware of that. There's probably so many thousand people out there that have built the ft mustang and spit, they know what amt makes it fly straight.

To BE clear, I want to BUILD the Right and Down angles INTO the FIREWALL for the BEEF motor using a gws 9x5 dd on an FT Mustang or Spit.

You know the funfly warbird in the video is 6.5 deg R with just a small 5.5 inch prop, makes me think more R and down thrust might be needed using a gws 9x5dd on an ft mustang.

Thank you
 
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#7
Is it safe to assume that if my motor/prop combo spins counter clockwise when viewed from the imaginary pilots perspective that I will want left angle instead of right angle?
 
#8
This is helpful, but if you are making your own plane how do you know what trust angle to but the propeller at, how come the bixler 2 has an upward angle.
 

Craftydan

Hostage Taker of Quads
Moderator
Mentor
#9
1. How much Left/Right thrust? Guess, fly, then tweak. Experience helps the first guess be closer to right -- sometimes close enough. Up/down? . . .

2. The Bixler (and the many others of the same design) is a pusher with a motor above and behind the CG. Up/down trust should be aimed to point the motor's thrustline through the CG of the craft. For a high pusher motor that means the prop will push downward on the plane (points up). For a low-wing tractor that usually means it pulls downward on the plane (points down). For a well balanced plane or well placed motor, the motor may be naturally aligned with the CG and a neutral thrust angle is perfect.