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-   -   Yak 55SP 2.6M converted to Turboprop!!! (http://www.rcuniverse.com/forum/giant-scale-aircraft-3d-aerobatic-110/11358532-yak-55sp-2-6m-converted-turboprop.html)

geh3 01-06-2013 08:20 AM

Yak 55SP 2.6M converted to Turboprop!!!
 
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Ilike turboprops and planes that land and takeoff easy and those that are "groovy"
SO the YAK fits this bill perfectly. SO I am in the process of installing a vintage but very good
WREN54 TurboProp into a Comp-Arf 2.6MYAK55SP + adding a smoke system as well
This TPputs out way over 50 lbs static thrust so the plane should be a spectacular vertical performer!
the color scheme will be very close to that seen below. It WILLbe a challenge to fit this particular TPin as it requires
enlarging the firewall and it will protrude into the fuse quite a bit.. but this hobby always has challenges so I am going to do it.
Ilike showing up at an airfields with unique planes that fly well so here goes. The plane will be decorated like the pics below



geh3 01-06-2013 08:32 AM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
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The TP unit is a heavy duty one with a 12mm propshaft and large bearings
so it should stand up to some agressive flying! Iwill modify the exhausts so they
are re-routed out the bottom of the cowl under and to the rear somewhat to maintain the
scale appearance of the nice cowl and louvers. Iwill use a russian ply mount piece
from another project to get the correct distance from the firewall and to add strength..
Ialso converted the TP to Kero Start using the available conversion kit listed on the Wren website


geh3 01-06-2013 09:06 AM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
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The first of many cuts! not for the squeamish HAH

gene6029 01-06-2013 12:40 PM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
Subscribed[8D]

Texastbird 01-06-2013 02:07 PM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
Kind of a Russian "turbo Raven", awesome concept!

geh3 01-06-2013 03:44 PM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
HAH yes Russian turbo raven

good one..it should be a screamer


geh3 01-07-2013 07:09 AM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
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OK I had to "redo" the Lg mounts to allow clearance for the TP starter motor..
nothing is ever easy when you put a TP in a non-TP plane.
BUT all of the wood I'm using for the various transition pieces are RUSSIAN
plywood! the stuff is really strong.. SO russian ply going intio a russian model... works for me...

geh3 01-07-2013 08:30 AM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
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moving on, there has to be some air intakes for any turboprop
I'm using one of the extra louvers supplied by C-Arf with this
plane! It will be pusitioned on the fuse bottom with the vents pointed forward so it can direct some air
inside the plane. Also I'm adding some robust russian ply gussets and some CF to the back sides
of the frp LG leg supports. This will vastly increase the strength here as these supports are only
held in by the bottom skin and a thin ply doubler...

and the beat goes on...

geh3 01-07-2013 04:05 PM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
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Ok the TP install is done at least from a mounting standpoint. I have
to give Wren some credit here, the radial mount is quite simple to do
compared to the other brands on the market that require front and rear mounting...
Now I have to do something with the exhaust...hmmmmmm

geh3 01-08-2013 02:24 PM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
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Moving on, I am converting the rudder from cable push-pull to direct servo action
I'm doing this because the TPI'm using weighs a tad more that the typical 100 cc gas engine
so having servos in tha back make balancing easier + Ihad a cable break once, making landing HAIRY!!!!!
so cutting holes for the servos as shown, using the same length servo arms as the C-Arf
phenolic ones were + I'm putting wood backers inside the fuse...

gene6029 01-08-2013 04:10 PM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
I have been following along & have a question. Is it possible to direct the exhaust down & under the plane, instead of exiting what looks like right in front of the wing? I'm thinking of a possible heat problem on the leading edge of the wing. From your picture it appears to be exiting between the two cutouts for the louvers & thats directly in front of the leading edge....Gene

nitro wing 01-08-2013 09:20 PM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
Thats how you keep the covering nice and tight :)

geh3 01-09-2013 05:18 AM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
I'm planning to add a short section of manifold on each side to direct the exhaust down yes.
On this plane, there is no wing covering, it is all fiberglass but the exhaust cools off rapidly as soon as
the propwash hits it. I will post pictures on whatever Iend up with

geh3 01-09-2013 09:15 AM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
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Rudder servos mounted.. this provides the requires throws
without the push-pull cables, one servo under each stab

FBaity 01-10-2013 06:42 AM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
I have flown the Comp ARF Yak-55 with the Wren 54 many times, great power when the Wren is running and gear box not locked up. Beware of dead stick glides as the airframe decelerates quickly even with considerable nose down deck angle. IMO the exhaust you are trying to build will not work. The main landing gear design and TP install is a failure point. Good luck.

Frank Baity
AMA 38026

geh3 01-10-2013 09:04 AM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
This particular TP has been massaged by Wren to eliminate gearbox failures.. it is a MKV
so I'm not worried about that. Ihave mounted this TPin the same manner in other planes as this one with "o" problems..
but I am concerned about the exhaust.. the safe thing would be to just extend it through the sides of the cowl, that way
there will be no extra back pressure, I'm still mulling this over.....
I repaired another YAK LG using the exact same technique shown here quite some time ago.. it is still flying.....

daveopam 01-10-2013 09:07 AM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
You do great work sir, but I have a question. Just to satisfy my own curiosity. Would you say the Wren needs more or less support than a 100cc Twin. I notice you doing a lot of reinforcement. I had assumed a turbine needed less "beefing up" of the motor mount due to the lack of vibration.

Thanks, david

FBaity 01-10-2013 09:15 AM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
The MK V will also fail the gearbox. Been there, done that.

geh3 01-10-2013 09:35 AM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
Idid beef up the firewall yes because this TP is quite strong for an older unit, it spins a 28X10 prop at almost
7000 rpm! SO I don't want the TP mount parting company with the plane. There is additional
support structure inside the plane that Ididn't photograph. Ilike building unique planes that are rare
but fun to fly.. hopefully Iwill be posting some nice videos soon...
Iforgot, my experience with TP's (Wren 44, Jet cat SPT5 )indicates that there is a LOTless vibration than with gas motors
especially if you are careful to balance the prop! BUTthere is a LOTof thrust there so you have to build robust I believe...


FBaity 01-10-2013 10:25 AM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
My experience with RC TP engines, Wren 54 all series in Tuscano, Raven, YK-55 and Wren 44 both series in J-3 cub and a Crop Duster, I know Ron Ballard well.My full size TP experience, Garrett TPE331 series in Mu-2, Merlin and Turbo Commander, Pratt and Whitney PT-6 in King Air and Platus Porter.

geh3 01-10-2013 11:43 AM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
The new series Wren 44TP is VERY GOOD, now with K start and amazing thrust when you consider the thrust turbine is only 10 lb
( good gearbox design ) Also the latest series Jet Cat SPT5 is also quite good, Ihave one in a Comp-Arf SF260 .. see...http://www.youtube.com/watch?v=io3fADGsWI8
Overall I have had excellent luck and a LOTof enjoyable flying with Wren products, and they have exceptionally good support!!!

geh3 01-11-2013 01:26 PM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
TurboProp test here>>>   http://www.youtube.com/watch?v=fGX7oicbWBY
this thing is a BEAST.. I had all I could do to hold onto the other end of the table
using my left leg and arm.. it starts and runs great with the Kstart conversion kit
which uses the newest Xicoy V.10 and quite small ECU.
Many thanks to Wren Turbines USA for the help...

daveopam 01-12-2013 07:21 AM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
Enjoyed the video and thanks for taking the time to answer my question.

david

geh3 01-12-2013 07:29 AM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
No problem.. I wish spring was here, this maiden should be a HOOT!!!!


geh3 01-13-2013 05:46 AM

RE: Yak 55SP 2.6M converted to Turboprop!!!
 
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Servos installed in 1 wing, I'm using the SWB Alu double lock ones with the
HDclevises included.. quite nice!


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