Great Planes Extra 300S

I've been building this kit for the last 6 months off and on and it's been a generally satisfying but occasionally frustrating experience.
Here is the state of play about 3 weeks ago.




This is the kit

Looks nice, but stop teasing us...what does it look like now?

Mike

MikeSeale wrote: Looks nice, but stop teasing us...what does it look like now?

Mike

Crikey Mike that was quick! I was going for a slow build up.

Part of the reason for choosing this kit was that I wanted to try a petrol engine. Great Planes specify a 60 - 90 2 stroke or 90 -120 four stroke so it looked about right for a 20cc gasser, a dle 20 being a likely candidate, and there a number of threads on rcgroups etc where people have done exactly this. Any way long story short with the help of an enticing offer from Probuild ( including club discount ) I ended up with an OSGT22 for cheaper than a DLE 20 + an effective after market Pitts muffler.




Being absolutely new to petrol engines I decided to bench run the thing first - the prospect of dealing with an unknown engine swinging a 15 inch APC meat cleaver made me slightly nervous but in fact it was a fairly straightforward process. I needed to spin it with a starter to get it to prime first off as the carb was dry but thereafter I've started it , hot and cold by hand. The only snags so far is that the engine is inclined to run backwards, apparently this a problem with the OS GT 33 as well, but a couple of clicks extra on throttle seems to cure this and of course the silencer bolts unscrew themselves. I've since fitted nordloc washers and these have been completely effective so far. The other snag was, being a complete dunce, I mounted the engine in the stand upright which meant I couldn't get to the carb needles with the engine running.

I've since had a problem trying to tune the needles which turned out to be due to a flat ignition battery - ok at low rpm but dying with the extra load when throttling up. Certainly made for some head scratching moments at the time!

Because of the extra weight of the engine I've had to mount the elevator servos at the rear of the fuselage which looks a bit untidy as there isn't much room, especially with standard servos and I thought I'd have a go with pull pull on rudder. I've used this effectively on gliders in the past so hopefully I've got it right this time. I ditched the CA hinges and fitted pinned hinges but apart some new metric hardware added to the original imperial fittings the kit is pretty much standard.

I've used Profilm for the covering and I employed some female help with the design of the graphics - I wanted a Union Jack version of the original Stars and Stripes scheme on the kit box art and she came up with some cracking designs which I didn't have the skill to implement. I ended up going with something fairly abstract.

So here's where I was about a week ago



Can you see a Union Jack in there?

Yes, it's uncanny, careful nobody mistakes it for a flag and tries to lash it to a mast !!!

Only joking, she's looking really good, am interested to see how she flies as I have David Tappins Goldberg bipe hanging in the shed. I want to get a petrol for this but like yours, I know it will make it nose heavy. The pilot winks at me every time I walk in and I can just hear him say ' Oi when you going to get me refurbed you bugger' I don't blame him getting angry, he's been hanging there for almost a year now and must have a splitting headache with the number of cracks in his head !!! soon I keep telling him soon.

Must be ready for maiden flight then Alan ? looking forward to seeing her in the air, just wondering whether your sure she has enough power ?

Tom

You have to look at it from the right angle honest Yes its all come out a bit heavier than I was hoping, at 36 ounces the OS is a bit of a lump but there is no shortage of power. Be interesting to see your Bipe with a petrol up front.

So here is what it looks like today:



The cowl is unfinished and as it's ABS may never be !!

Trial flights will be without the cowl as the engine is still new, luckily the CoG came out just right without the cowl fitted. She's come out at just over 9lbs without the cowl which is a bit disappointing especially as the cowl, unpainted, weighs in at over 6 ounces.

I'm planning to use a single 2000mAh LiFe running both RX and ignition to save some weight. So far I've done all the ground running using a 4.8v 1200mAh which seem to be fine so long as you keep the battery topped up.!

So apart from a bit of needle tweaking and general tidying up, its ready for a maiden on Saturday - maybe :ohmy:

Hi. Your new toy looks fab, I love the colour scheme, Bet it sounds great.

Hope you get it in there air soon...

Simon

Looks great, Alan. Did you cut the graphic by hand or did you send them off to a vinyl cutter? If hand-cut, I'm very impressed...I know how difficult it is to get abstract shapes looking the same both sides.

Mike