Dear RCI members,

Im planning to switch to Glow engines from electric planes. but was quite confused with selecting the right engine for the AUW.
Normally in Electrics, we choose the motor depending upon the thrust recommendation from the manufacturer and the final weight of our model.
but in engines there is no data on prop size vs thrust or the AUW recommendation for the engines, or may be i am unable to find those stuffs.
can any body guide me on this area or can anyone point me to any info on the internet where these resources could be found.

Ashok.P

Pass your email id i will send "SIG" rules doc file. it has everything about glow engines.

Check PM

Check your mail.

Got it Nitin,
Thanks a lot. i actually received this earlier from either sanjay sir or sundaram sir which i forgot, but the PDF is there in my mobile, i didnt know until today that this has those datas. thanks again.

Ashok.P

@v2 eagle
Typical large glow trainer.
5ft span, 2.5kg.
0.40-0.45 engine, turning a 10x6 prop at around 15,000rpm.
Cruise airspeed around 100-110kmph

Some data which may help:
OS 10LA 0.27hp@ 17,000 rpm
OS 15LA 0.42hp@ 17,000 rpm
OS 25LA 0.61hp@ 15,000 rpm
OS 46AX 1.6 hp@ 16,000 rpm

You can convert the hp to watts and see how it compares with your electric experience.

Nutshell , i would say Iyer sir,
Thanks a lot. is there a guide where we can convert this into thrust.
ie, i want to know exactly how much thrust is produced from engines of every CUI.
Sorry if im bothering you a lot.

Ashok.P

Try this:
http://personal.osi.hu/fuzesisz/strc_eng/

To tell you the truth, one does not need to start from scratch to estimate the power, prop, thrust required. All been done before. Usually one either has an engine and has to select a suitable model, or one has a model and has to select a suitable engine.
If you have a model or engine in mind, perhaps i could suggest a corresponding model/engine...

Im trying to build a 3 channel corro plane for a ASP 15 engine from rcdhamaka,
http://www.rcdhamaka.com/index.php?main_page=product_info&cPath=58_60_90&products_id=376

Im looking to see what should be the AUW or the thrust output from that engine for the recommended prop.
Also would like to learn any thumb rule for engine CUI vs thrust so that it would be easier for me in the future.For me once i got success with something, i would never stop experimenting.

Ashok.P

Remember to keep the wing loading in mind.

Source: adamone.rchomepage.com

Recommended Engine Size vs Wing Area
c. c.   c. in.   area sq. dm   area sq. in.
0.8   .049   12 - 16   200 - 250
1.6   .10   15 - 22   250 - 350
2.5   .15   20 - 30   300 - 450
4.0   .25   26 - 32   400 - 500
6.7   .40   32 - 45   500 - 700
10   .60   38 - 55   600 - 850

Powered model aircraft performance may also be estimated by calculating the
weight / power ratio, also known as power loading.
A slow and low wing loading (for a beginner), with a weight / power ratio of 440
to 500g/c.c. (270 to 300oz/c.in.) might be good enough, whereas an aerobatics
would need about 340g/c.c. (200oz/c.in.) to achieve good performance.
This is assuming 2-stroke engines and that the power of different types is pro-
portional to their displacements, (which isn't too far off).