Low Thrust !!!1
 

Guys on my ASP 52 I tried 12x4, 12x6 and 11x7 all Master Airscrew prop. The 11x7 is clocking 12600 rpm BUT there is low thrust. I felt maybe the engine is over revving with the 12x4 as it sounded so too but the thrust is hardly sufficient.

Any ideas or thoughts ?

Sunil

RE: Low Thrust !!!1
 

:eek: 12,600 with an 11x7 is not LOW THRUST. It's a very repectable figura for a non-piped .60, and an exceptional one for a 52.
I can understand a high revving 12x4 does not provide too much speed, but a lot of thrust for verticals...
I suggest to redo the readings...
Beppe

RE: Low Thrust !!!1
 

i mean i am getting the rpm BUT no pull or thrust. the plane is struggling and has not enough vertical

RE: Low Thrust !!!1
 

I fly the .52 myself and a 12-4 APC at high rpm does pull very very hard. If you lack vertical with this setup then your plane is too heavy and calls for a bigger and stronger engine. Your engine sounds strong too me, it is your plane that is the problem. What plane are we talking about and how heavy is it????????

RE: Low Thrust !!!1
 

According to the prop power calculator if it is turning that 11X7 to that RPM it is making 6.9 lbs thrust aand the pitch speed is 72.6 mph.

RE: Low Thrust !!!1
 

actually far from being heavy.... its the sebart 50 and weighs about 2500gms with fuel

RE: Low Thrust !!!1
 

since that isa a thrust to weight of over 2 to 1 I would think it should go like stink.

RE: Low Thrust !!!1
 

sorry thats 2500gms not 1500

RE: Low Thrust !!!1
 

Try an APC 11x5. On my 4*40 with TT46, ST51, or OS55AX- lots of speed and vertical. I have had better luck with APC for this engine size for the way I fly. On the 25/32, the Master Airscrew seem to work better for me.

RE: Low Thrust !!!1
 

you need more static thrust than what your plane weighs

RE: Low Thrust !!!1
 

According to my conversion calculator 2500 grams is 5.5 lbs.

RE: Low Thrust !!!1
 

u r correct

RE: Low Thrust !!!1
 

If your ASP XLS .52 turns that APC 12-4 at about 14000 or so it should rocket skywards a plane of 2500 grams (I think your engine is strong as you say that you are afraid to overrev it on a 12-4, which is impossible by the way) I really don`t understand the problem here, is the air thinner at your location or something???? since you don`t get the same pull as everyone else when turning a given prop at a given rpm???


If you turn the 12-4 in the high 13K`s approaching 14K and your plane is 2.5 kilos then you should be able to go vertical forever.

Bottom line is: Loose that 11-7 and use the 12-4 APC or 12.25-3.75 APC if you want thrust. That engine loves to rev and can tolerate ALOT more than these props. I have flow on a 9-6 turning over 18000 rpm static and the engine loves it.


Edit: I just noticed that you only use Master Airscrew props, but still the Master Airscrew 12-4 should turn up high rpm`s and pull like a mule. Let the engine rev;)

RE: Low Thrust !!!1
 

This may sound like a stupid question, but is the prop facing the correct way?

I agree with everyone else that on a 5.5lb plane with a 12x4 spinning at 13000-14000 that plane should have an amazing rate of climb. Even my 5lb Twist with a TT PRO.46 turning 13000 on an APC 12x4 would takeoff in 20 feet and rocket vertical as long as i wanted.

RE: Low Thrust !!!1
 

According to the Power calculator if the engine is turning a MAS 11-7 at 12600 it should turn a Mas 12-4 much faster in the neighborhood of 13500 and make 7 lbs thrust

The MAS 11-7 at 12,600 is honking on pretty good, That's getting into ST61 territory

RE: Low Thrust !!!1
 

Good post! My thoughts entirely. That's a very good figure for a .52 on an 11 x 7 and should shoot a 2.5 Kilo model skywards very quickly.

If you can buy APC props locally, try the 12 x 4 or the 12.25 x 3.75. With these two props, your .52 should do over 14,000 rpm and about 13,200 rpm respectively and deliver lots of static thrust.

Asmund's right - the ASP .52 is very tolerant of a wide range of props and will put out class leading power at anything from 12K to 16K and beyond. For peace of mind, put high quality bearings in the engine if you use sustained rpm over about 14K.

RE: Low Thrust !!!1
 

How about some basic stuff like:

Make sure the servo to throttle linkage is working ok and is supplying WOT when commanded.

When your going vertical the engine could be leaning out, try backing out the main needle 1/4-1/2 turns from max rpm.


Mike.

RE: Low Thrust !!!1
 

Seems his tach readings wrong or like mentioning before,props were wrong mounted.

RE: Low Thrust !!!1
 

here is a video of the plane with the engine. you could probably make out from the sound how the engine is performing

http://www.youtube.com/watch?v=wvVEjOYwjB4

RE: Low Thrust !!!1
 

I still suspect that he may be operating at higher than normal altitude.

His engine sure sounds strong judging by his stats. I have one (ASP .52 two-stroke) NIB right next to me on the old Ampeg guitar amp. Makes me want to bolt it to something hot and go flying.


Ed Cregger

RE: Low Thrust !!!1
 

Lol ... I am not a newbie please. Also the tach works fine :)

Also Ed the altitude is just about 500 ft over sea level.

RE: Low Thrust !!!1
 

Then, by all means, tell us why you think your engine is not performing to your expectations.


Ed Cregger

RE: Low Thrust !!!1
 

If you use the APC 12-4 and get it to spin close to 14000 rpm then you have about 8 pounds of thrust and your plane weighs 5.5 pounds. That is enough to hover and 3-D. From the tach readings you have provided I think your engine is fine.

If you had higher expectations than this, then our mind is the problem and not the engine;)

You actually do have GREAT THRUST from a class leading powerhouse as the XLS 52 is.

It is only your mind that makes you think you have a problem, nothing wrong with your engine at all;)

Maybe you are like myself and need a .91 engine in a 40 sizer to be really happy:D

RE: Low Thrust !!!1
 

After whatching your video I think your only problem is that you are afraid of letting the engine scream at high rpm:) If you want thrust at LOW rpm then you really need a fourstroke and a bigger prop;)

This is my recipy to get monsterpower from my XLS 52:
Remove the baffle inside the muffler, or even better order the Tower 46 muffler and put it on your .52 engine for serious increase in power.
The XLS actually love nitro and the more you give it, the more power it provides. I fly 30% helimix with great success, but it is still very powerful on 15% too.
Get rid of that master Airscrew prop and try both the APC 12-4 and 12.25-3.75.

Still not satisfied?? GET A BIGGER ENGINE;)

RE: Low Thrust !!!1
 

GUys did a static thrust test on the engine and its giving me appx 2700gms. which is more than adequate. BUT I am not feeling it in the response of the plane....................

The plane seems sluggish and underpowered ........