Engine choice ?

[Ernie]

Hi, If your cub is electric, then use IC, or vice versa. Then you will become bi-lingual. They both have their advantages

ernie

[cymaz]

IC or electric would depend on your club rules (we know some clubs have an ic ban because of the site), personal choice and the size of plane that's flown.

I love IC because I understand engines, I don't have any electric motors, ignorance is bliss.

I suppose if I was to start flying now then I would have gone the electric route. Engine reliability, ease of use, no cleaning, ease of maintenance. But I didn't , electric was in its infancy. No li-po chemistry etc.

Fliers now have so much choice it's now more difficult to make an informed choice. Cheaper batteries with increased capacity, small economical petrols, well made cheap glow engines from SC and ASP etc..

We've never had it so good. So engine choice for a particular type of plane type is more of a head scratching problem.

 

 

 

Edited By cymaz on 18/05/2014 09:01:12

[Jon H]

Posted by Steve Hargreaves - Moderator on 17/05/2014 21:36:03:

Posted by Jon Harper on 17/05/2014 20:36:27:

I have not flown them in some time as charging the battery up requires 6 hours of me sitting watching a charger (I have several 6s 3200 packs) and I do not have time for that nonsense.

You must be doing something wrong Jon...a Lipo will recharge in about an hour......provided you have a meaty enough charger....

Before telling me I am doing it wrong you should perhaps consider that I have 5 6s 3200's and a pair of 50watt chargers. As a result it takes 6 hours to charge up all of them.

In any event, in the type/size of model I fly electric has only one advantage and many disadvantages. As a result it remains confined to my park fly mx2 (not flown in 2 years) and my helis.

[victor field]

Hi guys

~Well, i'm now feeling suitably guilty for stirring up a hornets nest!!!!! Having said that, i am so pleased with all the replies from so many people thank you. It is so nice to meet (sort off), such a friendly and helpful bunch. It gives us beginners a real boost to continue.

Having groveled badly, listening to you all and picking the bones out of all the comments, i have decided. It will be an i.c. engine. Why, because my first plane 9the cub), is i.c. So I have some fuel a starter etc so no extra expense there. Reading all your posts I felt that both systems are equally as good but for reasons. So thanks to you all, I have decided when the Dove flys, I will start another smaller model to try out electric power.

I have had one suggestion to try a 40 i.c. motor in the Dove do most people concure with this, any suggestions welcome

Victor

[Peter Miller]

With a 49" span biplane a .40 FS should be fine but keep the model light.

If buying a second hand engine make sure that it is an OS. 40 Surpass The earlier ordinary .40 FS was not nearly as powerful.

You could even get away with a .48 Surpass as biplanes do have a lot of drag. You can always throttle back.

[Martin Harris - Moderator]

An underpowered biplane is not good news for a relative beginner to handle so my gut feeling would be to use a 52 four stroke - weight won't be an issue as you'll probably still need to add some lead in the nose!

My nearest experience is with a 40FS powered Flair Pup - this combination required careful nursing to gain height - very realistic but it now wears a 52!

With any rotary (or radial) engine model using a large open cowl, contrary to expectations, cooling can be a problem. Overheating will cause dramatic power loss or even deadsticks. I would always recommend using a dummy engine (or blanking plate) to shut off all air coming in to the cowling except directly in front of the cylinder - as mentioned above, adding extra weight at this position is likely to be to your advantage! You must also ensure that this air has an easy route to escape - if the cowling is a tight fit to the fuselage, ensure plenty of air can escape - twice the area of the inlet at least, perhaps a small mod to the fuselage at the bottom to make an air exit...

I've had fun convincing people of this in the past - but I can assure you that very little cooling of the engine goes on in those wide open spaces of an open cowl! The proof of the pudding has been in the eating, as they say.

 

P.S. One of the advantages of the numbers of people taking the electric route is the availability of second hand engines.  I've seen/heard of many bargains being had, particularly at club bring and buys.

 

Edited By Martin Harris on 18/05/2014 11:40:08

[Peter Miller]

Martin

Thinking about it, yes, the .52 would be a good choice too

I couldn't agree more about the cooling, that baffle really directs the air throught the fins. I have described this system several times over the years,

[cymaz]

You need power in reserve for a bipe, especially on landing. They slow up very quickly when reducing the throttle on finals. The extra power will give you time to open up the throttle and have more airspeed very quickly as and when needed. Fly it in under a bit of power.

[john stones 1 - Moderator]

Yes the 52 for me, the extra weight is useful and the bigger prop looks better.

John

[Rich too]

Posted by john melia 1 on 17/05/2014 10:30:24:

Well i was out of the hobby for approx 28 year, back then i flew ic, 28 years later i still fly ic/petrol. I like to mess around and tinker, i dont find tweaking the needle valve or setting up the engine a chore, i like the smell and the smoke trails across a clear blue sky (not that we get many of those).

I totally agree. I fly both, and I was initially smitten with the advances in electric. However, I am ultimately a petrol head, and if I had to choose I would go with IC - especially petrol..

Both are great, but in a scale plane like yours I would go four stroke glow - I recently purchased a Saito 40fs for my 30 year old Veron Tiger Moth...

 

Rich

Edited By Rich2 on 18/05/2014 12:52:34

[victor field]

ok chaps.

I'll follow your guidlines and go for a .52 or close to. I'll see what the shop has in stock tomorrow or the web!!!

Do you reckon follow the shops choice of prop or do I need to be careful here.

V.

[Martin Harris - Moderator]

I find an APC 12 x 6 works well and keeps the noise level down...

[Jon H]

A 52 will be excessive. The flair pup is much larger than the model we are discussing. As stated my flair Nieuport is 52 inches and about 5.5-6lbs (I never actually weighed it) and my very old saito 45 is more than enough power. I have in the past flown a 52 inch tiger moth on a 30 four stroke without a problem and a club member of mine has a flair se5a which is very much over powered with a worn out asp 61. The excess of power continually gets him into trouble with an excess of speed.

If you do use a 52 then use a 15x5 turnigy type A wooden prop. These run very fast as they have a narrow blade. My laser 62 will take the 15x5 to 8600rpm without issue so I would expect about 8000 from the 52 which will be plenty (after running in). I am also using a 13x5 turnigy type A prop on my nieuport. The little saito takes it to about 8000rpm. A newer saito 45 special adds another 600rpm to this.

[Martin Harris - Moderator]

While I agree that a 52 will give more power than is required to power the Dove, the choices of new engines will be limited if going smaller. I've flown a Flair SE5a on an SC52FS and found it well suited. The sesquiplane Nieuport is probably a lot less draggy with its token gesture lower wing.

Perhaps your clubmate could fit a lower pitch prop if he's unable to manage the throttle correctly. This would give him the benefit of better acceleration and climb and limit the maximum speed.

If you get a biplane into a high drag, low speed situation with a lower powered engine then things can turn nasty rather quickly.

[john melia 1]

I have an ultimate 40 bipe fitted with a 52 two stroke, it now has a 13x5 prop on, and its still pretty fast, , but as the guys say once the power is off it loses speed very quickly, with the glide angle of a brick. Mine has to be flown in under power at all times.

I find the extra power helps with the landings, if i'm short then i have plenty power at hand to pick it up again

[victor field]

Hi

Thanks everybody for your advise. I have bitten the bullet and ordered a 52 i.c. and a 12 x 7 prop.

I have bought a bottle of Schnapps ready to celebrate just in case it does fly (properly).!!!!

Thanks again

Victor

[Lee Smalley]

this always ends up the same, respected names come on and slate one power mode or another, glow is noisy and oily/messy or electric is dangerous and likely to blow up in a minutes notice !!! if you have nothing positive to say, i do wish you would button up!!

both power options have pros and cons, both are brill.. personally i prefer IC, but i am grown up enough to acknowledge electric is also great, please guys if a person come on asking for some advice please be grown up about it and give impartial advice only and actually try to help the guy make an informed choice!!

[Jon H]

I would not use a 12x7 prop. the pitch is too high and the model will fly too fast. look for something with 5 inches of pitch. A 13x5 master airscrew would be a reasonable choice after running in.

[victor field]

Thanks Jon

suggestion noted. Will have a word with the shopkeeper when the engine arrives.

[Jon H]

No worries, The 12x7 would be ok (at a push) for a sport/aerobatic model but I would always use a 12x6 for that application on a 52. For your application you need thrust more than speed and the 13x5 will give you that. A friend had this combo on a 55 inch se5a. It was overpowered but not so much that it could not be tamed! Given that the saito 45 seems to have been discontinued the 52 was probably the best choice looking forward to the future. Just make sure you run the engine in correctly. Disregard any instruction that says you need to run it slobbering rich for hours on end as all you will do is break it. Treat it more like an ABC two stroke and get it running quite fast with a small prop (11x6) and leaned out to about 90% of peak performance and use little 5 second bursts at full power to bring the rpm and temperature up to where they should be. If you have any questions about it let me know

[Braddock, VC]

With all due respect to Jon, I'd follow the makers instructions to the letter, after all they have more to lose than any forumite.

I have and I've no regrets.

[victor field]

Thanks both

The engine doesn't arrive for a few days so I have time to change the prop size or buy a couple to experiment.

I have built a running in jig ready to run-in my first engine and will take on-board everyones comments on the correct proceedure. Does this modelling lark get any easier, I had this daft idea that I was returning to a nice relaxing hobby!!!!!!!!!

[Jon H]

Its a simple fact that the ASP/SC instructions are wrong. While normally I would promote the idea of reading the big book of words that came with it in this instance they usually lead to an engine with soggy compression. I have recently run in 3 sc/asp engines for club mates using this method and it works well and even after many months they still have good compression where as normally it falls away. it does require some care though as you don't want it to overheat. It should still be a little rich and for the first tank at least full power should only be used for 5 second periods. I work with engines every day and for reasons of metallurgy and other things running the engine slow and cold will only damage it. Im not saying thrash it, but its got to be up to operating temperature/rpm and the light load prop allows this without having to run it very lean. As I said, 90% leaned off will be plenty. When it comes to running in the next one I might try and take a video to show what I mean as its nowhere near as drastic as it sounds.

As for getting easier..i suppose its a matter of perspective, to me running in an engine is easy but as I have been operating them for over 28 years as well as building and designing them for 3 I suppose I have an unfair advantage! Everything is easy once you know how to do it

[Steve Hargreaves - Moderator]

In what way are the ASP/SC instructions wrong Jon? My ASPs usually come from Just Engines & are suppled with instructions written by the late Paul Landels who set up Just Engines.....

[john stones 1 - Moderator]

A bit more reassuring from me Victor

It will get easier, no doubt about it, using engines is easy to pick up, me I followed makers instructions, worked for me. Props ? again recommended ones works for me, it gives a varied selection to suit your type of model. Had dozens of them found them easy to use and reliable.

John