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Nov 06, 2014, 12:13 PM
Watt Waster
Tsavah's Avatar

Yak 17


Nice performance from this foamie.
Latest blog entry: Center of Gravity - Airplanes
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Nov 06, 2014, 08:48 PM
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Kevin Cox's Avatar
Looks and flies great Robertus!
Nov 11, 2014, 10:06 AM
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robertus's Avatar
Thread OP
Unfortunately I crashed today. I forgot start timer and I've discharged the battery away from me.
Yak-17 EDF Crash (3 min 17 sec)


Ready for rebuild
Nov 13, 2014, 12:36 AM
Watt Waster
Tsavah's Avatar

Yak 17 Crash


I was surprised to see the model crash and was wondering why you couldn't glide it down after the motor cut out? I am assuming the receiver also lost power and the plane was no longer under control.
Last edited by Tsavah; Nov 13, 2014 at 12:36 AM. Reason: spelling
Nov 13, 2014, 01:51 AM
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It's was my fault. It was too far from me. Hard for me to observe the behaviour of the model and I was worried that I'm was landing near the building, so I've decided to hard turn on low speed, and I lost lift.
But hey, don't worry, damages are easy to repair, I have to build front section only.
Nov 25, 2014, 12:39 PM
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Rebuild in progress..
This time I want to build different type of intake, just for my knowledge.
Something like this

And this time I've tried harder and made round intake not oval

Nov 26, 2014, 10:30 AM
Watt Waster
Tsavah's Avatar
Looks like a good recovery.
Latest blog entry: Center of Gravity - Airplanes
Dec 06, 2014, 09:22 AM
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robertus's Avatar
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Finished, at last.

Dec 07, 2014, 02:10 PM
Watt Waster
Tsavah's Avatar
Impressive repair work. I bet it flies well again.
Latest blog entry: Center of Gravity - Airplanes
Jan 16, 2015, 06:47 PM
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park aviator's Avatar
I have a laser cutter and am thinking ill cut all the parts first befor I assemble mine.Tod.
Mar 11, 2015, 03:20 AM
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robertus's Avatar
Thread OP
Re-maiden flight after repair.
Jak 17 EDF 70mm (3 min 28 sec)

Winter was over, time to flight.
New type of inlet didn't change anything in flight characteristics.
Still I have to a little mix throttle to elevator to prevent climbing with increasing power.
Besides that, Yak flies very well
Mar 12, 2015, 11:53 AM
Watt Waster
Tsavah's Avatar

Yak Climbing with throttle Increase


Wondering if that can be fixed with a slightly nose heavy model, or a reduced incidence between the main wing and stabilizer?
Latest blog entry: Center of Gravity - Airplanes
Mar 12, 2015, 01:22 PM
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Yak soars very well, without engine. I have to be careful to not miss the landing field.
Climbing is not precisely word. It's rather a torque from engine, especially in quick acceleration. On hand launch is very noticeable and there is a risk to stall (without mix).
Mar 19, 2015, 07:33 AM
Registered User
Hi, I have been following this build quietly and enjoying it. Your rebuilt model really shows some good performance.

I had a Hawk model with a 50 mm fan unit that rolled with the torque of the motor annoyingly and also needed a correction to the thrust line of the nozzle to prevent it from nosing up with power. Rather than mess with TX mixes I went to the heart of the problem by adding a small wedge inside the nozzle exit at the top to deflect the flow down and another on the left to deflect the flow right to correct the tendency to roll due to the torque and turn left. This is analogous to down and right thrust in a propeller driven aircraft and I think is preferable to TX mixes since it addresses the thrust/torque problem directly with no time delays, just like the down and right propeller correction does. The wedges are made of foam and stuck on with UHU Por. The side thrust wedge on my model is 4mm in height and 11mm long (20deg wedge angle) and 10 mm wide. The down thrust wedge is about twice the width. It reduces the nozzle area (original nozzle exit diameter 45mm), which puts up the thrust a bit but otherwise there do not seem to be any other side effects.

Since the wedges are mounted with their bases in the exit plane of the nozzle, they are visible but they are not very obtrusive. I believe that wedges were commonly used in full size aircraft with fixed geometry tail pipes to adjust the thrust-temperature-RPM relationships for the individual gas turbine engines. I am not sure how obvious this technique is. I haven't seen it mentioned anywhere, but it is easy to install and to modify or remove if it doesn't suit.
Apr 06, 2015, 04:02 PM
Registered User

Work in Progress


This is my first build in a little over 2 years. Thanks for the plans... and the inspiration to start building again.


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