c.of.g
| weasel | 20/02/2009 09:14:01 |
352 forum posts 6 photos | hi can anyone, advice me on the balance point. on the black horse chipmunk. it says 100mm from leading edge. i have fitted a sc 52 & about 200ton of lead to correct balance, is the engine powerfull enough, feels far to heavy on the nose. regards weasel.. |
| Martin Harris | 20/02/2009 09:51:40 |
3833 forum posts 104 photos | First off, how does it compare with the all up weight quoted for the model?
Which end have you stuck the local church roof in?
Is it a 2 stroke or 4 stroke SC52?
The recommended engines go up to a 91 4 stroke which seems rather excessive based on my experience of the Airsail kit which is @ 5" larger span and weighs 8 lbs dry and flies very adequately on a 52 4 stroke. Of course, the 91 4 stroke will be considerably heavier than either a 52 2 or 4 stroke which may explain the lead required assuming it's in the noisy end....
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| weasel | 20/02/2009 10:13:17 |
352 forum posts 6 photos | hi martin, i can not find the all up weight for the model, the engine is a sc52. 2 stroke. the lead anvil is stuck on the bulk head inside the cowl, aswell as the battery. would you reccomend a heavier engine, regards weasel, alnwick..... |
| Martin Harris | 20/02/2009 10:41:38 |
3833 forum posts 104 photos | As the engine is ahead of the bulkhead then a heavier engine would reduce the AUW to achieve the same C of G. Sometimes, putting a larger engine in can spoil a model by making it too heavy but in this case you need the weight anyway.
Perhaps someone out there with experience of the actual Black Horse model would be better placed to make a recommendation before you spend any money and of course, it depends on whether you're looking for scale performance or just want to fly it like a sports model.
...and of course, you can always use the throttle if you go larger!
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| Marko | 20/02/2009 17:10:16 |
459 forum posts 94 photos | Hi Weasel lm flying a chippie from blackhorse with a OS91 4stk supass ,ive also put the rx batt on top of the engine bulkhead and some lead inside under the tank shelf to ballance l did some mods to mine eg scale exhaust and stuff so you will have to play around with yours it flys realy nice l hope this helps.......................mark
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| Brian Cooper | 21/02/2009 01:37:26 |
192 forum posts 4 photos | Yeah, I have got the Blackhorse Chipmunk. Mine has an ASP 91 F/S in the front, and the Rx battery is as far forward as it can go. It also has a small amount of lead weight to get the G.G in the right place.
It’s a lovely aeroplane to fly.
B.C. |
| Clive Matthews | 21/02/2009 13:00:36 |
335 forum posts 32 photos 1 articles | Hi Weasel,
With a Saito 100 fitted 5mm forward of the suggested position and a 5 cell AA pack as far forward as possible, mine balances 10mm behind the suggested C of G ie. 90mm from leading edge. In flight it is very pitch stable and gives the impression that the C of G could be even further back. I think that Blackhorse have suggested a very conservative C of G.
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| weasel | 21/02/2009 15:00:28 |
352 forum posts 6 photos | thanks klive, i am going to take out the sc52 which seems to light & might be a little under powered. i have a new sc 70fs & will try that. thanks for your information. regards weasel.. |
| Ken Lighten | 23/02/2009 08:32:09 |
89 forum posts 10 photos | Hi Weasel,
I have the chipmunk with an ASP 70 fitted (the same as a SC just about) with the battery pack fitted in the top of the engine mounting box, everything else as per the Black Horse instructions - flies a dream
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| Scott Cuppello - HobbyKing | 07/03/2009 10:22:17 |
794 forum posts 78 photos | Have just electric converted one and flown it this morning, no doubt about it, C of G is too far forward, I'm going for moving it back as per Clive's test, then I reckon it will fly as well is his obviously does. |
| Wimbledon99 | 27/04/2011 19:17:04 |
23 forum posts 4 photos | Hi Gents, I know this is an old thread but fingers crossed. The engine template is for a 2 Stroke. How are the 4 strokes best mounted. Cheers |
| Clive Matthews | 27/04/2011 21:23:12 |
335 forum posts 32 photos 1 articles | Hi Nigel, inverted does it, just like the real thing! |
| Wimbledon99 | 27/04/2011 21:24:52 |
23 forum posts 4 photos | Many Thanks Clive ![]() |
| Biggles' Elder Brother - Moderator | 27/04/2011 21:55:28 |
Moderator 9036 forum posts 473 photos | Just reading through this thread and I'm amazed! I have an OS 91 FS inverted in mine, I don't remember shoving the batter particularly far forward, and I have about 14g of lead - in the tail!
BEB |
| Clive Matthews | 27/04/2011 22:53:04 |
335 forum posts 32 photos 1 articles | The only reason for shoving the engine forward was to make it fit. There isn't quite enough clearance for the carb on a Saito.
Maybe you used rather a lot of epoxy on the firewall
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| weasel | 27/04/2011 22:58:27 |
352 forum posts 6 photos | Hello biggles, i had to add a canny bit of lead to the front end and also the battrey was on the front engine mount box. it flew well untill a mid air with a ready trainer put pay to it. Hope see you again this year at the walsall fly in. Regards Weasel... .. |
| Biggles' Elder Brother - Moderator | 27/04/2011 23:10:27 |
Moderator 9036 forum posts 473 photos | Hi Weasel,
great to hear from you! Yes I'll be at Greenacres - looking forward to having a chat with you again and catching up! See you there mate!
BEB |
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