Dave S. Posted January 21, 2021 Share Posted January 21, 2021 Hi all, just taken delivery of an 80" Seagull Chipmunk and intend to get it put together soon - just need to finish the Wot 4 re-fit and Acrowot currently on the bench. I would like to use a petrol engine for this - but not sure which one. The last (and only previous) model of this size I have had was a DHC 2 Beaver which I flew with an MVVS 26 petrol turning an 18x6 prop - it flew well but definitely wasn't over powered, so the suggestion in the destructions for the Chipmunk for a 20cc petrol strike me as potentially underpowered (thinking of safe take-offs from grass rather than aerobatics). Would the OS GT33 fit and be a good match? It is only a little more expensive than the GT22. It's nearly 15 years since I last flew petrol, so the market has changed and I am not familiar with it. Any suggestions on engine choice would be most welcome, though it has to be petrol - not glow at this size and most definitely not electric! Thanks in advance. Quote Link to comment Share on other sites More sharing options...
BackinBlack Posted January 21, 2021 Share Posted January 21, 2021 This may be of interest: Laser Engine Developments Petrol engines with a difference and you won't have to spend a fortune on a silencer! Quote Link to comment Share on other sites More sharing options...
Dave S. Posted January 21, 2021 Author Share Posted January 21, 2021 That is interesting - last Laser engine I had was a 75 in an Acrowot sometime in the late 80s. The 180 glow looks idea, but I would rather go with a petrol if possible. Good suggestion, thank you. Certainly not something I had considered. Let's see what else pops up! Quote Link to comment Share on other sites More sharing options...
Anthony Scott 2 Posted January 21, 2021 Share Posted January 21, 2021 I fly my SG Chipmunk from a grass strip. It is powered by an SC 120 4 stroke which is more than sufficient power. Quote Link to comment Share on other sites More sharing options...
Dave S. Posted January 21, 2021 Author Share Posted January 21, 2021 Posted by Anthony Scott 2 on 21/01/2021 11:39:57: I fly my SG Chipmunk from a grass strip. It is powered by an SC 120 4 stroke which is more than sufficient power. Thank you, that's useful information. I reckon an OS GT22 should be on a par with an SC 120 4 stroke. I have now removed the model from the box, looks very well built and covered (I'll send my daughter round to tell them if it's not as she lives in the same city as Seagull at the moment!). Bit of a struggle to fit the wings & fuselage into my very crowded modelling room as it has a desk, a wall-length workbench with Bandsaw, pillar drill & bench vice, four assorted models (not including the Chipmunk) plus a shelf full of kits, half a dozen bass guitars, bass amp and speaker and another shelf with a couple of hundred CDs…and somehow, I have to get in there and make things! Quote Link to comment Share on other sites More sharing options...
Jon H Posted January 21, 2021 Share Posted January 21, 2021 We recommend our 100 glow for this model. Its not heavy at under 11lbs and the 100 offers more than enough performance for beyond scale performance. Many are choosing to fit 155's but the model performs more like an extra than a chipmunk. If you are looking at petrol 2 stroke, 15cc would be plenty or perhaps a 20cc petrol 4 stroke. Clearly its a preference thing, but i would try and find a 4 stroke for it (petrol or glow) as a tinny 2 stroke isnt really the right fit in my view. Quote Link to comment Share on other sites More sharing options...
Dave S. Posted January 21, 2021 Author Share Posted January 21, 2021 Thank you, Jon, your advice is greatly appreciated. I don't like over-powered scale models, though they are less likely to cause a problem than an underpowered one, in my experience. One reason I am biased towards petrol for this model is the cost, but more importantly, the availability of fuel. I used to be able to buy fuel from my local model shop, but that closed a few years ago, so now I am depending on there being some shows this year or driving quite a distance to get fuel. I do prefer the sound of a four stroke, but the lower revving petrol engines with a decent silencer aren't too bad in my opinion - my Beaver didn't have that big radial sound (obviously) but it didn't sound too much like a flying chainsaw either. Thanks again, all advice and opinions welcome. Quote Link to comment Share on other sites More sharing options...
Jon H Posted January 21, 2021 Share Posted January 21, 2021 You can get fuel shipped from modelshop leeds, kings lynn and a number of other shops. If you buy 4 gallons the shipping cost is not so bad when split between the 4 bottles. If you are only flying small ish engines 4 gallons will last a good long while. My biggest moan about petrol is the smell. It gets everywhere and makes me sick. bleh Quote Link to comment Share on other sites More sharing options...
Alan Gorham_ Posted January 21, 2021 Share Posted January 21, 2021 I buy my glow fuel online and it is delivered by courier. It is faster, cheaper and more convenient than either driving to my nearest model shop or driving to a show and paying entry. Glow engines are generally cheaper to buy than their petrol equivalents. I'd want a four stroke engine in a Chipmunk in preference to any brand of petrol 2 stroke. Quote Link to comment Share on other sites More sharing options...
Dave S. Posted January 21, 2021 Author Share Posted January 21, 2021 Must have been looking in the wrong places - I couldn't find anywhere that would deliver fuel. I'll have a look at the places suggested, thank you. The smell of petrol is a good point, I have to keep my models in the house these days and petrol does reek a bit... Quote Link to comment Share on other sites More sharing options...
Bruce Collinson Posted January 21, 2021 Share Posted January 21, 2021 Glow ...Laser ...MSL couriered fuel ... Laser low oil mix ...; petrol; NOISE. No idea how much space there is in a Chippie cowl but my direct and observational experience of a 20cc petrol is that by the time you've got anywhere near 82dB, a decent glow 4 stroke wouldn't have cost much more. I remain to be convinced that you can lose the irritating "bark" from a 2 stroke petrol without either strangling it, or hanging a pound of cobbled together muffler from the outside of the plane. Smell. Very frugal though. BTC Quote Link to comment Share on other sites More sharing options...
Braddock, VC Posted January 21, 2021 Share Posted January 21, 2021 Westonuk deliver glofuel foc if bought in 4 x1gallon amounts. Use aspen fuel for petrol engines, no smell.. You can buy it ready mixed about £22 a gallon. Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted January 21, 2021 Share Posted January 21, 2021 I'm no great fan of petrol 2 strokes but this view of the internal arrangement of a home brewed (by the previous owner) silencer on my Z38 works very well (within 82dB suitably propped) and removes the ringing bark typical of 2 strokes. Quote Link to comment Share on other sites More sharing options...
Dave S. Posted January 21, 2021 Author Share Posted January 21, 2021 Lots of good ideas coming through, thank you everyone who has contributed so far - any more ideas - please keep them coming, all giving me food for thought. Quote Link to comment Share on other sites More sharing options...
Ady Hayward Posted January 27, 2021 Share Posted January 27, 2021 I have a Laser 120 in mine and she's nicely powered. The engine is quite compact and has plenty of headroom (Foot room?) inside the cowling. 1 Quote Link to comment Share on other sites More sharing options...
Dave S. Posted January 27, 2021 Author Share Posted January 27, 2021 Thanks, that's another for the list. Good colours on your Chipmunk, once mine's flight proven I might be tempted to change the camo for something more traditional. Quote Link to comment Share on other sites More sharing options...
Low pass Pete Posted February 12, 2021 Share Posted February 12, 2021 Mine has an OS120 with a Just Engines Turbo Header Exhaust. Very good combination Quote Link to comment Share on other sites More sharing options...
Manish Chandrayan Posted August 23, 2023 Share Posted August 23, 2023 On 21/01/2021 at 17:09, Anthony Scott 2 said: I fly my SG Chipmunk from a grass strip. It is powered by an SC 120 4 stroke which is more than sufficient power. Hello Anthony Is your tank located at the standard factory location or did you cut the mounting area to lower the tank height? I am mounting an Enya 120 and really not happy with the tank mounting height that is designed for Walbro equipped petrol engine or for mounting batteries in an electric version. On the other hand cutting the tank mount is likely to weaken the firewall integrity. Same question for Low Pass Pete since both of you are using more or less similar powerplants Quote Link to comment Share on other sites More sharing options...
Anthony Scott 2 Posted August 25, 2023 Share Posted August 25, 2023 Hello Manish, Sorry for the tardy response. My tank sits on the bottom of the engine box, several cms back from the firewall. The fuel tubing goes thro the original hole. Quote Link to comment Share on other sites More sharing options...
Manish Chandrayan Posted August 25, 2023 Share Posted August 25, 2023 (edited) No worries Anthony thank you for taking time to reply. I assume that when you say bottom of the engine box, you mean the factory provided tank location? Or is it suspended from the factory tray? Or is the tank actually resting on the curved fuse bottom? Did you have to resort to some sort of surgery on the model to get the tank where you have it? Thank you Edited August 25, 2023 by Manish Chandrayan Quote Link to comment Share on other sites More sharing options...
Anthony Scott 2 Posted August 25, 2023 Share Posted August 25, 2023 Please see the attached photo. The tank is a square SLEC item, I think 14oz, it projects approx 6mm above the former immediately behind it. Surgery was required! Quote Link to comment Share on other sites More sharing options...
Manish Chandrayan Posted August 25, 2023 Share Posted August 25, 2023 Perfect! That explains it quite well. Since the cut out is quite away from the firewall it leaves enough meat and will not seriously compromise the firewall strength (hope so). Have you encountered any iengine running ssues due to the distance from the engine? I am planning to use a Sullivan 14oz tank. Neat idea of installing a shelf to take the Just engines on board glow battery etc. Thank you once again. I will take the scalpel and get on with it. Quote Link to comment Share on other sites More sharing options...
Anthony Scott 2 Posted August 26, 2023 Share Posted August 26, 2023 No problem with the longish fuel feed. Quote Link to comment Share on other sites More sharing options...
Manish Chandrayan Posted August 26, 2023 Share Posted August 26, 2023 Thank you for patiently answering. Happy landings 👍 Quote Link to comment Share on other sites More sharing options...
Manish Chandrayan Posted August 28, 2023 Share Posted August 28, 2023 Based on sound advice, here is what I have done. Surgery to the tank tray, installed cross grained ply,spruce and bass braces to tieup the formers where opportunity existed. Happy with the tank position now Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.