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How Small a Prop can be used for DLE35ra?

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Old 11-02-2018, 02:45 PM
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noobdude
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Default How Small a Prop can be used for DLE35ra?

hi all i am thinking of putting a 16 size prop on DLE35ra to be used in a Senior Telemaster scratch built.
Can i put that small a prop on dle35ra? i am thinking of 16/6 or 16/8.
recommended props for del35ra are 18, 19 and 20 size. but i have issues with ground clearance. and i dont want to go with a 20cc as i am planning of putting this engine in a future plane after a while.
looking forward to your suggestions. thank
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Old 11-02-2018, 03:32 PM
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A 20cc engine will need a 16x8 to keep rpm's in check. That's WAY too small for a 35. You need a 3 blade prop maybe? Or go WAY up in pitch, to something a war bird might use. Like a 16x10 or 16x12
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Old 11-03-2018, 11:16 AM
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Originally Posted by ahicks View Post
A 20cc engine will need a 16x8 to keep rpm's in check. That's WAY too small for a 35. You need a 3 blade prop maybe? Or go WAY up in pitch, to something a war bird might use. Like a 16x10 or 16x12
achicks as you know from my post on the other forum, i have changed my mind am not going for the dle35ra now for my current project of senior telemaster. but still i am curious as if a very small prop been fitted on 35, by small i mean literally out of league for this engine then will it damage the engine? as engine will not be loaded up if i put a lets say 15/8 prop on it and it will rev without much load, will this damage the crank shaft? i have heard about it from someone but could not find an answer.
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Old 11-03-2018, 12:32 PM
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IMO if you were to run any of these reed inducted gas engines past 9,000 rpm you will have failures pretty quickly.
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Old 11-03-2018, 12:49 PM
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Originally Posted by speedracerntrixie View Post
IMO if you were to run any of these reed inducted gas engines past 9,000 rpm you will have failures pretty quickly.
I agree completely with the above. These engines all have cantilever crankshafts (supported only in the front) with a single counterweight and are simply not intended for high RPM operation. Add to that the reeds may not be designed for high speed operation and may fracture or otherwise fail. If prop length is an issue, get a taller LG or run 3 or 4 blade props to properly load the engine. If you need / want high RPM operation, get a Zenoah or something similar with a crankshaft designed for that.
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Old 11-03-2018, 02:33 PM
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My question would be why the want/need for a smaller prop than what is reasonable .... I totally agree with the above posts . A small prop on the DLE 35 will only achieve premature failure from over reving the engine. Anything above 9000 rpms sustained will ensure a short engine life. A 16x10 three blade would be the absolute minimum prop I would use and even then you need very good throttle management.
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Old 11-04-2018, 04:44 AM
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Originally Posted by noobdude View Post
achicks as you know from my post on the other forum, i have changed my mind am not going for the dle35ra now for my current project of senior telemaster. but still i am curious as if a very small prop been fitted on 35, by small i mean literally out of league for this engine then will it damage the engine? as engine will not be loaded up if i put a lets say 15/8 prop on it and it will rev without much load, will this damage the crank shaft? i have heard about it from someone but could not find an answer.
The prop size is used to determine the load on the engine. Too big a prop/load and you drop the engine rpm's too low to develop it's max horsepower/torque potential. Some engines really like a small prop, turning up rpm's like a champ and sounding like a glow engine. They can even make a lot of power at those high rpm's. The issue is, they won't do that long. The bottom end will end up coming out the side of the case. At that point, about the only part you could use over again is the carb.....
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Old 11-08-2018, 12:54 PM
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Originally Posted by speedracerntrixie View Post
IMO if you were to run any of these reed inducted gas engines past 9,000 rpm you will have failures pretty quickly.
Originally Posted by Truckracer View Post
I agree completely with the above. These engines all have cantilever crankshafts (supported only in the front) with a single counterweight and are simply not intended for high RPM operation. Add to that the reeds may not be designed for high speed operation and may fracture or otherwise fail. If prop length is an issue, get a taller LG or run 3 or 4 blade props to properly load the engine. If you need / want high RPM operation, get a Zenoah or something similar with a crankshaft designed for that.
Originally Posted by CK1 View Post
My question would be why the want/need for a smaller prop than what is reasonable .... I totally agree with the above posts . A small prop on the DLE 35 will only achieve premature failure from over reving the engine. Anything above 9000 rpms sustained will ensure a short engine life. A 16x10 three blade would be the absolute minimum prop I would use and even then you need very good throttle management.
Originally Posted by ahicks View Post
The prop size is used to determine the load on the engine. Too big a prop/load and you drop the engine rpm's too low to develop it's max horsepower/torque potential. Some engines really like a small prop, turning up rpm's like a champ and sounding like a glow engine. They can even make a lot of power at those high rpm's. The issue is, they won't do that long. The bottom end will end up coming out the side of the case. At that point, about the only part you could use over again is the carb.....
i understand what you guys are saying.
can you guys suggest any gas engine in 10cc range that can safely rev around 16000 rpm with a 11" 3 blader.
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Old 11-08-2018, 01:32 PM
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Not possible.
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Old 11-08-2018, 03:41 PM
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I waited for someone else to say it first. +1 to what speedracer said.

Going back to your first post, is there a reason you don't want to extend the LG on the Telemaster for more prop clearance? Or are we talking about a different airframe now? On a plane like a Telemaster, a large diameter, low pitch prop would be normal for decent performance. A relatively small diameter, higher pitched prop would just scream while being a bad match for the airframe.
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Old 11-09-2018, 12:01 AM
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Originally Posted by Truckracer View Post
I waited for someone else to say it first. +1 to what speedracer said.

Going back to your first post, is there a reason you don't want to extend the LG on the Telemaster for more prop clearance? Or are we talking about a different airframe now? On a plane like a Telemaster, a large diameter, low pitch prop would be normal for decent performance. A relatively small diameter, higher pitched prop would just scream while being a bad match for the airframe.
I am sorry for causing the confusion, yes my first post was about telemaster and we have decided on a dle20 with 14" prop for that with a little extended landing gear.
but when i asked for 10cc engines, i was comparing them to 60 size nitro in my mind and just straight away asked which made confusion.
and yes i was asking for another airframe without clearly mentioning again my mistake.
basically i have two 2stroke ASP 61 engines laying around, one has some good flight time on it and the other one barely has one flight on it and both are in boxes since a year, they will need a service to clear out gumming, but both are in good condition.
ASP mentions 2000 to 18000 rpm range for these engines. i havent checked the rpms my self but from youtube videos there are tests where they can rev a 1106 prop at 12000 rpm.
i was thinking about putting them both in a twin engine plane and get the highest possible speed out of them without damaging them, and then i was thinking if i could get same performance from a gasser of small size as the airframe will be around 72" span so bigger engine is not an option.
i want to keep the sizes nearly as scale as possible as it will be a war bird and i dont want it to sit on way too tall lgs or have out of scale props as bigger engines demand.
i apologize for making confusions and too many questions, but as my nick says Noobdude
any info will be appreciated.
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Old 11-09-2018, 05:07 AM
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Well, here's one piece of info. Already mentioned is the fact 20cc engines most commonly use 16 and 17" props. If you're planning on a 14", it's going to need to be a pretty special prop....
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Old 11-09-2018, 11:40 AM
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Originally Posted by ahicks View Post
Well, here's one piece of info. Already mentioned is the fact 20cc engines most commonly use 16 and 17" props. If you're planning on a 14", it's going to need to be a pretty special prop....
props listed for dle20 are 14x10, 15x8, 16x6, 16x8, 17x6, 18x6 according to tower hobbies tech data. we can accommodate a 16" prop as well.
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Old 11-10-2018, 08:47 AM
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The benchmark prop for the 15cc gassers is 14-6. My Evolution 15cc is a bit stronger than a Saito .91, both running the same 14-6. I would think a 15cc would fly the Senior Telemaster nicely.
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Old 11-10-2018, 09:59 AM
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Agree on the 15cc Telemaster.

Go ahead and try that 14x10 and get back with us on your impressions.
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Old 11-10-2018, 11:55 AM
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On my Great Planes Super Skybolt ARF I'm running a DLE 20 with a m18 X 6 no problems realy turns up.
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Old 11-12-2018, 07:50 AM
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Originally Posted by noobdude View Post
props listed for dle20 are 14x10, 15x8, 16x6, 16x8, 17x6, 18x6 according to tower hobbies tech data. we can accommodate a 16" prop as well.
DLE 20cc Gasser! (Data & Links 1st Post)

( 1 2 3 ... Last Page)
jedijody

Here is where we have been gathering info on this engine since 2010. I have 2 and have been running them on 16x8's and 17x6's exclusively because of the great info in this thread started by jedijody.

In this long thread much has been written about over RPM and engine life. You say you want to put this in another plane someday. If you prop it so on the ground static RPM goes over 8400, the engine will not live long.

You know that we always take the manufactures prop data with a grain of salt.

Go ahead and throw out all the great advice given here. It is your choice.

The MA 15 x 8 three blade has been used with good results.

Last edited by kmeyers; 11-12-2018 at 07:55 AM.
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Old 11-12-2018, 11:17 AM
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Originally Posted by kmeyers View Post
DLE 20cc Gasser! (Data & Links 1st Post)

( 1 2 3 ... Last Page)
jedijody

Here is where we have been gathering info on this engine since 2010. I have 2 and have been running them on 16x8's and 17x6's exclusively because of the great info in this thread started by jedijody.

In this long thread much has been written about over RPM and engine life. You say you want to put this in another plane someday. If you prop it so on the ground static RPM goes over 8400, the engine will not live long.

You know that we always take the manufactures prop data with a grain of salt.

Go ahead and throw out all the great advice given here. It is your choice.

The MA 15 x 8 three blade has been used with good results.
there is some really good info in this thread i will definitely consider your advice, i am here to learn from you fellows
thanks for the link
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