Hello

[Rob Cope]

Hi again RC,

I presume you've decided by now, but the main difference between I/C and electric is personal preference and how much kit you already have. I love I/C and really am at pains to admit that when I do, I might have to build a 4-engine plane with... I can't come to say it... not I/C.

Anyway, I'm an I/C fan asyou can tell. It's the battle to start them, the raw power (and a bit of noise) and the tinkering into life. If you are a sparks (I'm BSc Hons IIIrd (oops) (nested brackets - oops) (and again) Electronic Engineering) and you love precision and absolute start/stop (which I don't) then carry on down the electric route - but note an extended fuel tank for I/C is light. More batteries are not.

If however, you want a machine that lives and breathes fire and has "moods" then battle it and go I/C.

Also the Mode1/Mode2 choice is non-trivial.  I'm mode 2 now (almost irrevokably) but I've heard say that mode 1 is "better" of aerobatic menouvres - but other Mode2s call then "tank drivers" so do find out from experienced members of both camps what their considered benefits/drawbacks are before plumping.

Regards,

RC

[Peter Miller]

Flying an I/C twing is far more exciting and flying on one engine calls for real piloting skill. I likened flying my last twin (American Nightmare, (Named long before 9/11))  to a ride on a really wild roller coaster.

I must build another twin soon. I really need the adrenalin rush.

Maybe I should do a four engined one. I still have the plans for my old C/L B-17, scale it up a touch and.....!!!!

[Rob Cope]

Thanks Peter,

Once we've rebuilt the cloakroom and I've learnt how to make my Sportsman Aviation Spit run reliably - turning an inverted TT61 into a side-mounted TT61, I'm sorely tempted to go for the "ASM" "Lockheed C-130 Hercules" ARTF (SMC) as it will take 4 x .30FS which I'm hoping to put into a plan-built Halibag later...  It's just too easy to resist and not that pricey really (apart from the four engines of course)....  and will teach me four-engine discipline before the precious hand-crafted crate gets out there...

I know it's american and all that, but the RAF probably fly the  C-130J by now, so it's sort of alright.

Regards, Rob 

[Peter Miller]

Why worry about wether it is American or not? I build planes because I like them, not because of their nationality.

The SC 30s should be nice and a sensible price. Think of the sound, really curls your toes.

Why is an inverted engine any less reliable than any other position? I never have that trouble. I am currently flying two models with inverted engines, My Marauder aerobatic model with an inverted O.S. 28F and my Symphony aerobatic model with an SC 32 which is almost inverted. Always used to use inverted engines in Scale and Stunt C/L models.

[Rob Cope]

Thanks Peter,

The spit has an inverted engine and it is always flooding, cutting, hyrau-locking, etc.  Very hard to start.  I've re-plumbed it twice now.  First time I made the same mistake as the original builder - allowing the pipes to squash when the tank moved whilst attaching the wing.  Anyway, I've heat-modified the back of the tank and it now fits beautifully.  However I got it to start for the first flight and it cut out with 1/2 a tank left.

After that all it would do is flood all the time.  I have to close the needle straight after a flight and only open it before the next start otherwise fuel tends to run everywhere.  Perhaps the silencer is the problem?  It's a cylindrial box with a vent pipe in the side.

Anyway, with the flooding and locking, I thought at least a side-mounting would prevent any slight flooding putting the glow plug "out " and would give me a minute's extra leeway to get the thing started.

I'm not exactly at my wits end with this, but I'm running out of ideas.  I used to start it upside down (engine right way up) and then turn it over to fly, but the set-up is very tricky as it needs to start one way up and run the other way... What I really want is for it to start right way up (engine inverted.)

Regards, Rob 

[Peter Miller]

With the engine inverted any fuel flooding into the card will drain straight out, not go through the engine. This makes me think that it is flooding via the silencer. The pressure pipe in the tank should end above the fuel level, it would seem that it doesn't. There is a way to cure that one if you don't want to go back into the tank. You can buy a non-return valve from any fish tank stockist. they only cost about a £1. (There is a bloke on ebay selling them but he charges £2 for postage, rip off time again!)

Cutting after a short time in the air could be due to the clunk jamming against the end of the tank(Did you shorten the pipe when you modified the tank?) or a nick in the clunk pipe where it is fitted to the tube that goes through the bung. This is easily done. Did it myself (Again) only a few weeks ago

If possible I would suggest dropping the tank. The top should only be a little bit above the spray bar in the carb.

Hope that some of this helps.

[Myron Beaumont]

TIP      I always round off all pipe ends before pushing tubing on (called de-burring)

[Former Member]

[This posting has been removed]

[Rob Cope]

Anyway, sorry to drag everyone off thread. 

RC. Howare you getting on with your decisions and have you got your eye on a plane yet?

Regards, Rob

[RC]

Update Time.

The decision has been made for me, in my local paper the other night was an advert " Model airoplane, FREE to a good home".

Geuss what, it was a Robbe Euro Trainer in "used" condition but nothing that a bit of trim tape won't sort out. It's already got an I/C engine mount and tank and all control links and servo arms.  Yes I know I'm a jammy b***er but hey I'm skint !

Anyway, next job is to source a 0.46 engine and I really think it will make sense to go the 2.4 radio route, then it's time to start frustating the trainers at my local club, they seem very nice, I wonder how long that will last once they are buddied up to my ham fists

Any suggestions on prop size ? I was thinking of an 11X6.

[Bruce Richards]

A good strong .46 will be fine with a 11X6 but check the ground clearance on you model first. You may want to go for a 10X7 or 10X6 to give more ground clearance for the prop.

[Peter Miller]

The 11X 6 would be a better bet and it will be quieter than the 10" props.

SC 46s are on offer to the trade from Perkins at the moment so you should be able to get a good deal on that. Great engines.

[RC]

Thanks for the advice,  I will see if any deals show up with the SC 46's, I am also watching some engines on fleabay. 

[Peter Miller]

Try Galaxy Models for the SC 46

[Rob Cope]

Hi Peter,

Sorry not to answer your last question. Yes I did shorten the clunk and it was still rattling after the cut-out.

I've not got much leeway to adjust tank/carb height as the propshaft is of course fixed height and the tank is also owing to space. There's just no room for manouvre unless I move to a 4 oz tank and that wouldn't be practical.  All I have is engine rotation to adjust carb height, so I'll see where it should end up - maybe 1/2 inverted or something like that... 

The vent is curved and diagonal cut to just clear the top of the tank, so it can't be started inverted any more.  I'll investigate non-return valves.  I guess you have to drain the tank through the carb pipe then... 

This is rather inaccessible on the Spit (without breaking the spinner and cowl down each day.)  Not good.  I wonder if I could tee off another access pipe for drain-down in the carb pipe?  How are the non-return valves when draining the tank?. Do they let enough air through?

I must admit I've never measured up the tank/carb height.  I assumed everything was OK when I bought the thing.  It's very hard to measure with the bits being "buried" different sides of the firewall. I'll have a measure first and that should lead me to the correct rotation for spray-bar to 3/4 tank match-up.

Thanks once again, Rob

[Peter Miller]

IT will not matter if the vent is under the fuel level while starting inverted.

From what you say you are only using two pipes out of the tank. If I can't get at the carb to drain I use a filler and a line from the silencer plus the supply to the carb.

I would imagine that the tank is in roughly the right height anyway if the model has been designed reasonably.

[Rob Cope]

Hi Peter,

I have three pipes.
One is the filler - plugged whilst starting.  This ends in the tank about 2/3 up.  I guess I could invert the plane and drain the tank throught the exhaust pressure tube?  This may be easier to access.  I'm still trying to find and empty lunch-hour in which to measure all this lot up.  Still working during the day.  Only 44 you see....

Regards, Rob 

[Peter Miller]

Yes, you can invert the plane to drain the tank.

These days I use two clunks. One to the filler and one to the carb. That way I can drain through the filler wihtout inverting the plane.

[Kevin Corrigan]

Thought I'd pop in and say hello too. 

[Rob Cope]

Hi Peter,

Two clunks is a good idea. I've not heard of that one. I'll see what I can do. That'll ease the draining - and with the non-return valve - brilliant.

Hi Kevin.  You new to this sport?  Welcome whatever the answer. 

Regards, Rob

[Rob Cope]

So,

From your silence, RC, we must all assume you've found your engine, kitted up and you're out flying all day... is that it?  How are you getting on?

Regards, Rob 

[RC]

Thanks for the "jog" Rob. I do shift work and most of my PC time is meal breaks at work so on-line time can be a bit patchy.

Yes I have a nice new SC 46, run in and rareing to go but I am taking my time on the refurb' of the plane as it's probably going to be all I will be flying for the next year or so. I could have just put the engine and radio gear  in and been in the air by now but a few things that I found with the donated Robbe Eurotrainer means that it is currently having a front end refurb'.

The original metal clamp type engine mount is being replaced with a plastic replacement and the fixings for the engine mount are also being improved by the use of captive nuts so I can change the mount etc if I need to. The original just had screws and glued over bolts inside the bulkhead. That's almost complete and then I am going to install a better throttle to servo linkage as the orriginal was not suitable for the SC anyway.

Once that's all done, servo's and radio gear go  in next  and balance up with the radio battery and ballast as required.

Then get it checked out at the club and watch it take to the air, can't wait, but work keeps encrouching on build time.

As I said, I could have just put it all together and hoped but that's not my style, it may "only" be a trainer but it's still my first real plane and I want to put as much of me into it as I can.

Regards, Ian.

  

[Bruce Richards]

Ian,

I'm with you. If I get a second hand air frame I go over it with a fine tooth comb and always find something I am not happy with. I just think of how it would feel if I flew it and it crashed because there was a problem lurking that I left unfixed. 

 Good luck and enjoy the flying. I must say I shook like a leaf for my first dozen flights but I enjoyed it and still enjoy it a year later. Totally addicted.

Bruce 

[RC]

Thanks Bruce, I just know I will feel better that by doing what I'm doing will help me to know my plane better.

[RC]

Update again for anyone remotely interested

All bolted together, radio installed and tested to the best of my ability, been working in the shed and garage every spare bit of time Iv'e had getting the plane and my super modified tool box / trolley / plane stand (?) built and mighty pleased how it all came out, worked right up till late Saturday in the hope that the weatherman was going to be wrong 2 days in a row (he got Saturdays forecast wrong in my area) but ............well you geussed it, Sunday morning and Snow.

Feeling very deflated as I really wanted to see it take to the air (I know it will be someone else giving it the maiden) but hey that's what I expected. Just starting 7 night shifts so it's going to be 2 weeks away before I might get to the club field. Just hope it's good weather !!!!!!!