Kingtech Turbo Prop Engine
#101
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David, I just got the Biela prop which is supposed to be the preferred prop for the engine. It says it is a 24 x22 3 blade. Have sent one of them to Tru Turn to have a spinner cut for it. Does anyone know the prop bolt size on this engine? I need to either buy a spinner adapter or make one? Thanks
Tommy
Tommy
#103
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David,
I'm running the SEP 24/17/3. It gives me the exact performance I was looking for on the Raven which was a good balance of speed and vertical which I didn't have before.
On the PC-21 I would think you would want a little more speed; and since we have some data on the SEPs, you would probably be right in the ballpark with a 24/18 or 24/20, but I'm not sure of the sizes available. If you're looking for a Biela, then I'm sure the numbers may shift slightly due to the of composite vs. wood.
Let us know what you come up with.
I'm running the SEP 24/17/3. It gives me the exact performance I was looking for on the Raven which was a good balance of speed and vertical which I didn't have before.
On the PC-21 I would think you would want a little more speed; and since we have some data on the SEPs, you would probably be right in the ballpark with a 24/18 or 24/20, but I'm not sure of the sizes available. If you're looking for a Biela, then I'm sure the numbers may shift slightly due to the of composite vs. wood.
Let us know what you come up with.
#104
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Curious to know what propeller (diameter, pitch, and maker) many of you are using on your K-60tp? I am still searching for a prop that will provide the best performance (speed/vertical climb) for my PC-21. So far, I tried the Fiala 24x17 and the SEP 24x22. Had to reduce engine rpms for the Fiala prop, and could not spin the SEP 24x22 higher than 3000 rpms on the ground. Biela prop should be delivered tomorrow, but doubtful the results will be any better. Unlike testing props for a glow, gas, or electric setup, trying to find the right match for this puppy can get pretty #@×n expensive. Would greatly appreciate comments from those of you using the Kingtech K-60tp.
Kirk
#105
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David, I just got the Biela prop which is supposed to be the preferred prop for the engine. It says it is a 24 x22 3 blade. Have sent one of them to Tru Turn to have a spinner cut for it. Does anyone know the prop bolt size on this engine? I need to either buy a spinner adapter or make one? Thanks
Tommy
Tommy
Kirk
#106
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Mine weighs 40 pounds without fuel in the main tank and a full UAT. Haven't weighed it with fuel. I have all of the equipment installed as far forward as possible and did not have to add nose weight to hit the CG. The main fuel tank is on the CG so there is no change in CG during flight. Not sure on the measurements of the Tucano but the PC-21 has a wing span of 90 inches and a fuse length of 112 inches.
Kirk
#108
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Kirk,
Thanks. The Tucano has a 110" wingspan and weighs around 53 pounds at takeoff.
The reason I asked is that I have seen Chief's fly at Kentucky and yours online. I have also been following with interest the prop pitch discussions. After watching your video and you supplying the aircraft information, I have to think you guys are heading in the wrong direction. Video can be deceiving but it really seems like the PC-21 is really lacking in performance. I think the prop pitch is way too high and you are losing a tremendous amount of thrust as a result. I can post videos of my Tucano when new and had the Gen 1 Jet Central motor, which does not put out the power that the new generation units (of all brands) put out and the performance is staggeringly improved over what I have seen with the PC-21 Keep in mind the Tucano is heavier and almost 2' more wing...which is drag.
I don't know what the gear ratio is on the KT TP but over pitching and bogging down the motor is never a good combination. Trust me...you could put a 24/12 3 blade on it, dive it full throttle towards the deck and you probably won't hit 8 grand. Of course if there is a design limitation on the KT unit and you have to keep the revs low that's different but my experience tells me that you guys are killing yourselves performance wise by over propping.
Just throwing my .2 cents in...
Boli
Thanks. The Tucano has a 110" wingspan and weighs around 53 pounds at takeoff.
The reason I asked is that I have seen Chief's fly at Kentucky and yours online. I have also been following with interest the prop pitch discussions. After watching your video and you supplying the aircraft information, I have to think you guys are heading in the wrong direction. Video can be deceiving but it really seems like the PC-21 is really lacking in performance. I think the prop pitch is way too high and you are losing a tremendous amount of thrust as a result. I can post videos of my Tucano when new and had the Gen 1 Jet Central motor, which does not put out the power that the new generation units (of all brands) put out and the performance is staggeringly improved over what I have seen with the PC-21 Keep in mind the Tucano is heavier and almost 2' more wing...which is drag.
I don't know what the gear ratio is on the KT TP but over pitching and bogging down the motor is never a good combination. Trust me...you could put a 24/12 3 blade on it, dive it full throttle towards the deck and you probably won't hit 8 grand. Of course if there is a design limitation on the KT unit and you have to keep the revs low that's different but my experience tells me that you guys are killing yourselves performance wise by over propping.
Just throwing my .2 cents in...
Boli
Boli,
Mine weighs 40 pounds without fuel in the main tank and a full UAT. Haven't weighed it with fuel. I have all of the equipment installed as far forward as possible and did not have to add nose weight to hit the CG. The main fuel tank is on the CG so there is no change in CG during flight. Not sure on the measurements of the Tucano but the PC-21 has a wing span of 90 inches and a fuse length of 112 inches.
Kirk
Mine weighs 40 pounds without fuel in the main tank and a full UAT. Haven't weighed it with fuel. I have all of the equipment installed as far forward as possible and did not have to add nose weight to hit the CG. The main fuel tank is on the CG so there is no change in CG during flight. Not sure on the measurements of the Tucano but the PC-21 has a wing span of 90 inches and a fuse length of 112 inches.
Kirk
Last edited by bevar; 10-22-2015 at 02:51 PM.
#112
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It will be a P-51 style spinner, three blade, 4.25 inch diameter. I sent them a blade so they could custom cut it. You need 50% of the material remaining in order for the spinner to be flightworthy and I think i was cutting it close, considering the size of tis prop. It is going on the Airtractor
#114
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I don't have a build thread. It is 144 inch WS, weighs in the neighborhood of 38 pounds. All scratchbuilt from Duane Habets plans. Ply, foam, balsa, glassed, with CF inside for strength. The wheels are 6 inch, the gear strut is 5/8 inch custom bent. It is 1/4 scale version of the two seat military version of the AT-802U. Has two bomb drops under the belly and wing racks with have missile launchers when complete.
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rc-cropduster (05-21-2022)
#117
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The exhaust stacks were made by Tam. I think they are the same ones that fit the Jetcat turboprop. I cut them and shortened them up for my purposes. Have not run the engine yet, maybe this coming weekend if all goes well. Hoping for 5200 rpms on the ground, and 7000 in the air.
#118
Join Date: Apr 2005
Location: KatoombaNSW, AUSTRALIA
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Hi David and George
Well I bit the bullet and bought a Kingteck turbo prop mounting it into my pc21 i will try a 26x14 Beila 3 blade on it where do I get exhaust extensions from can;t believe they don't supply them
Well I bit the bullet and bought a Kingteck turbo prop mounting it into my pc21 i will try a 26x14 Beila 3 blade on it where do I get exhaust extensions from can;t believe they don't supply them
#120
Thread Starter
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Good luck with PC-21. Curious, are you mount that 26" diameter prop on a Skymaster PC-21? The reason for this question, I've been using a 24" diameter prop on my plane, and notice how little clearance there is between the tip of the prop and the ground. So just wondering if prop/ground clearance is going to be a problem.
#121
Join Date: Apr 2005
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Hi David
This a true 1/3 scale pc21 made by Aerobell in in Switzerland fully built up no longer made fuss 10ft10in long wingspan 8ft4 in from memory it will weigh 51lbs
I have a photo of it on my models on this site not a problem for ground clearance with that prop.
This a true 1/3 scale pc21 made by Aerobell in in Switzerland fully built up no longer made fuss 10ft10in long wingspan 8ft4 in from memory it will weigh 51lbs
I have a photo of it on my models on this site not a problem for ground clearance with that prop.
#123
Thread Starter
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I have tried the SEP 24x22 three-blade prop, but was not able to spin it higher than 3500 rpms. Tach may have been the issue. Also ran the Biela 24x22 three-blade prop which seemed to have much higher rpms, closer to 4750. Haven't run the engine since late October, but plan to get back to it by April. Will let you know how the PC-21 performs with the Biela prop, don't plan to use the SEP prop.
#125
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After a year of fitting and testing, and finding parts that would work, the AT802U finally flew with the Kingtech turboprop. The engine flew this 50 pound plane with no issues. I wish the software had some type of feedback system that could be used with the telemetry to give us the engine / prop rpms. I never got the engine about 70% on the throttle and she took off in less than 200 feet with no flaps. This was a great base model for my first turboprop airplane. The taildragger configuration makes it a little tricky but for a good pilot it would be no issue.