How small will they get??
|Steve Hargreaves - Moderator||29/04/2012 17:43:48|
6730 forum posts
Anyone seen the new NGH9 from Just Engines.....a 9cc petrol motor..looks very nice but quite expensive
I can't help feeling this is a bit small though....a glow 52 will probably produce more power & will certainly be much lighter....the petrol motor will use less fuel for sure but I can't help feeling we are in an area of diminishing returns here...
55 forum posts
1.75cc FROG 1948
611 forum posts
Interestingly I've just been reading an article in the November 1983 edition of Radio Control Models and Electronics (yes, it had the full title them days!) all about an electronic ignition system for converting a Super Tigre G20 glow to spark. The point made in the article also related to the need for much less fuel on board which would compensate for the weight of the ignition system and reduced power from the motor. And of course, the lower cost of pertol compared to ethanol based fuel.
|John Privett||30/04/2012 00:38:53|
5996 forum posts
0.8bhp at 15,000rpm is quoted for the petrol engine. Not exactly a powerhouse then!
|ken anderson.||30/04/2012 08:07:17|
8504 forum posts
more novelty/fascination value than anything...same as the 'irvine diesels'....... remember them.....where are they now?....
ken anderson ne..1...... novel dept.
|Phil Claridge||30/04/2012 08:25:50|
1924 forum posts
i used to have a very small .19 petrol motor complete with belt driven fan
|Delta Whiskey||30/04/2012 10:04:03|
1320 forum posts
With the cost of Nitro fuel these days, I can't wait til they develop more to really compete with the smaller glow in the 40 arena size !
Nearly £20 for my 10% Nitro compared to around £6 for gallon of petrol which lasts a lot longer - will the glow finally die out ?
|Lee Smalley||30/04/2012 13:00:32|
2125 forum posts
firstly i can't believe people pay so much for fuel, a gallon from weston inc delivery is 12 quid, why people use 10% and above is beyond me i have 2 moki 180 that only use straight fuel, which is even cheaper sub 10 quid and it drinks no more than petrol as its so powerful i rarely go above half throttle so a tank lasts almost as long as petrol, combine that with the additional weight and batteries etc i prefer the big glow route at the minute big engines need far less nitro, even straight so the cost/benefit factor below 20cc is in my opinion pointless
|Delta Whiskey||30/04/2012 13:40:37|
1320 forum posts
Good point Lee, though I guess it's just mainly as I need the higher nitro % for the heli's which I started out with, (remember these run at 100% in Idle up) and got used to the Bekra with 18% oils and then got the lower 10% which is the lowest Bekra go too for the planes, I have to say they don't even seem to get too hot after 10 mins of fast flying ! I do have some 5% somewhere of another brand but it's years old and I don't trust it !
Without hijacking this thread on glow fuel issues it's still a lot cheaper flying petrol !
|Steve W-O||30/04/2012 14:05:06|
|2775 forum posts|
Where is Weston? A quick search doesn't give me a website, maybe it is local.
|Michael Hickman||30/04/2012 14:32:51|
312 forum posts
Weston UK ? Teynham, Kent (01795 521030)
Edited By Michael Hickman on 30/04/2012 14:48:54
|Lee Smalley||30/04/2012 15:05:36|
2125 forum posts
correct Weston UK buy four gallons for sub 50 quid delivered, i generally buy it this way as its much cheaper and liquid gold is fine for all my engines bar my moki and big super tigres
|Lee Smalley||30/04/2012 15:14:43|
2125 forum posts
a gallon of petrol cost about £6.50 depending where you live plus then the oil you need prob around 7 quid a gallon, then factor in the higher cost of the engine ST2300 £134.00 versus £200 plus for petrol then add the ignition kill switch and batteries plus the hassle of keeping them charged etc and i think glow does not work out that bad, i can buy an awful lot of fuel for 80Quid, true petrol will eventually work out cheaper but its not the golden egg some profess it to be !!
still love petrol engines by the way !!!
|Daithi O Buitigh||30/04/2012 15:52:04|
1360 forum posts
They're only expensive at the moment due to slow take-up. Once that improves, watch the prices drop as production runs get bigger
|Paul Marsh||30/04/2012 17:52:57|
3788 forum posts
I'm sure the 0.8HP for the NGH 09 is wrong. For a 9cc engine, that is quite pathetic - not enough to blow a skin off a rice pudding!
I reckon it's 1.8, as 0.8 would be quite useless. As I'm thinking of buying one, I'll wait until someone test it...
|Reno Racer||30/04/2012 18:05:26|
1138 forum posts
RCGF have been supposed to be releasing a 10cc petrol for some time as well.
In my mind the best option for a 40 size engine, if you want ease of running, ecominical fuel use and no excessive weight is to use a IC/Nitro 4 stroke. Unless you have a short nosed airframe that needs a lot of nose weight (WW1 bipe etc), then its difficult to justify adding all that extra engine and ignition weight. For that size model the different in tank size (and hence weight) beteen a FS and a petrol is lost in the extra weight of the petrol engine. You would also then need to add a super silencer to keep the noise down. A small petrol FS would be better, but not at Saito's prices.
I reckon a 9cc petrol mus really equate to a 30 2 Stroke, if it 0.8.
|Alan Cantwell||30/04/2012 19:19:14|
|3039 forum posts|
I fly petrol motors for one reason, reliability, try as you may, you will never get away from having to twiddle a needle, we have just concluded the test flights of a 118" B25, powered by 2xzenoah 38s, primitive engines these days, but we have utter trust in their ability to simply keep going, downside--and the only downside of petrol for me is the smell, even this can be overcome by buying special petrol, with an anti smell additive, below 20cc though, i really cannot see the point
|Paul Marsh||30/04/2012 19:33:00|
3788 forum posts
I've got a couple of the RCGF 15cc engines. Been using one in a Yak 54. Originally had a OS 108BX-1, but find the airframe is much cleaner and the engine is quite good. Not massive power, but enough for sportsman aerobatics.
The smell, I don't like, which reeks if spilt, or on a hot day vents from the tank/container.
|Reno Racer||30/04/2012 21:00:31|
1138 forum posts
I also have RCGF engine and do love their cleanliness, cheap to buy and cheap to run and their relieability/dependability. have a 15cc in a 60 size Edge 540 and a 26cc in a 1/4 scale Nieuport 11. Next buy ( I think) will be a beam mounted 20cc for a 90 size airframe.
I've found all my RCGF engines run much better after a couple of hours running and the increase in RPM and HP is very noticeable once their bedded in and proped correctly. On the flip side, I had (briefly) an SV17cc. Good relieable engine, but heavy and no power. 1.5 HP compared to the 15cc RCGF which kicked out 2.1. The SV could just about keep a 60 size airframe in the air at WOT, the RCGF was tons better and flew my Edge 540 in the right manner.
Be interesting to see if these NGK smaller engines are like the SV?
Right about the smell. I try and keep my planes in a spare room, but petrol starts getting me nagged. Of course, I empty the planes petrol tank and don't store the fuel in the house, but as soon as you remove a fuel pipe, stopper or even rotate the prop, the smell wafts out.
|Simon Chaddock||30/04/2012 21:19:22|
5544 forum posts
I would have to agree that really small petrol engines have no practical advantage over glow and 4 strokes even less so, unless for some reason fuel economy is absolutely vital.
This scratch built (but not by me!) 5cc 4 stroke is reasonably powerful and light for its size but even lightest ignition system adds a significant amount of weight.
It was built before 'transistor' ignition was available so it has a conventional coil and points.
It was built to attempt the model plane world endurance record when the maximum total weight was limited to just 10lbs so it runs on pure petrol with recirculating dry sump lubrication.
The FIA abandonned the endurance record before any attempt could be made.
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