Extra 300 S ARTF with different design

[Vecchio Austriaco]

Back after a little break (sometimes I have also to work to finance my hobby) I installed the glow plug extension. The only disadvantage I can see is that in case the plug has to be replaced it will be a nice fiddling job to open the hex socket screw which fixes the cable to the plug.

Worst case will be to remove the cowl. But I trust in OS plugs and hope that they will work for some time.

This is the coax socket which will connect plug and battery. I am not happy with the

hole in the cowl, it looks like it has been done by hungry mice. If there is some time I will make an aluminium flange to cover it.

 

But before that I start looking at the cockpit. First of all I lowered the cockpit 2 cm, otherwise the pilot figure would show only its head (Like the original figure which was in the kit). As the pushrods for the tail controls, which are running below are quite low, it was an easy job. Then I added the seat, or lets say the little bit of the seat you can see. All the lowered part and the seat I painted black.

 

As I did not find a pilot figure which looks like Mr. Rottland, the pilot of the prototye, I purchased Ken and I had to find out that Barbie figures are totally out of fashion. So I got Ken for 3,99€, quite cheap. The only snag is that here you do not find any accessories like sunglasses or headsets any more.

 

So I has to do the headset myself. No problem, a piece of aluminium strip, a lathe and some patience and the headset is done.

Ken has been cut in half and after that fixed to the seat by 2 self cutting screws. For sure painful. I had to torture also his arms, as I bent them into the right shape using a hot air gun.

 

 

The instruments I copied from a picture I found in the internet and printed them on photo paper in the right scale. I don't understand why Graupner puts here a totally basic and bad designed sticker. Its so easy to find a matching photo and the whole thing looks much more real.

By the way - for the gurus: This is the cockpit of the rear seat of an Extra 300L as I did not find a proper one for the Extra 300S. But the differences are very little.

 

Now I have to get out the sewing machine as the guy needs some safety belts too.

VA 

Edited By Vecchio Austriaco on 21/03/2010 11:30:46

[Vecchio Austriaco]

The belt production was done in a few minutes. I found a woven polyester tape which is normally used for decorating parcels. I folded the tape twice to get the right strenght and size and sewed along the two edges.

 

 

Test fit with the belts in place. Now I have to fix the cannopy to the fusselage.

[Vecchio Austriaco]

Some time has been lost by different business trips but finally I had the time to finish my baby.

 

I installed receiver and battery and checked all control surfaces to be sure that no moving part got blocked during building. For the divided elevator I use a Y-cable, as I had a six channel receiver available which doesn't allow mixing of the elevator halfes. All cables except the battery lead are hidden below the servos and are fixed by a piece of foam rubber.

 

I use a 1800 2-cell Lipo as power source together with a Power Box Digi Switch, which regulates the voltage down to 5,5V and shows me also if the battery is discharged.

Due to the weight problems I described further up (plane quite nose heavy) I tried to go as far back as possible with the switch and the battery.

So the switch is behind the wing now, but this gave me also the possibility to install it in the dark blue part of the fusellage where it is almost invisible.

 

A test on the scales showed 3030 g without fuel. Another test for the COG showed that thanks to Ken (pilot) and the battery position the COG is correct. So with fuel it will be again a bit nose heavy, but better that then tail heavy.

 

So here it is - ready for the maiden flight

 

 

As you can see the weather is perfect as well, but unfortunately it is rather windy and also the fuel proofer which I applied yesterday should harden for a longer period.

So I need to wait until next weekend.

VA

Edited By Vecchio Austriaco on 05/04/2010 14:51:05

[Vecchio Austriaco]

To reduce waiting time I will take tomorrow afternoon off. The weather forecast is good and another advantage is that the number of people around the field should be less on a Friday. (so not so many of my mates will see my baby crash)

 

I tested the engine this evening - and that was a good idea as there was a short in the remote glow plug connection. Found and corrected. The engine starts within a few seconds and I am quite satisfied.

 

Batteries charged, stuff packed.

 

So tomorrow same time you will get a notice if this thing flies or not.

VA, slightly unpatient.

[Vecchio Austriaco]

Here we are with the report,

 

earlier then expected as I had to leave the field being wet up to the knees and with a broken model.

 

But now in detail. Engine set up was not of any problem, at first trial I noticed a strong pulling force to the left. Could be a mixture of tail wheel plus thrust angle. I corrected that by some degrees offset of the rudder and started carefully correcting with the rudder. Another minor problem are the screws holding the cowl, the vibrations of the engine (reinforced by the cowl) made them come loose. Have to search for a better solution.

 

 Take off was no problem, after a few meters the Extra was airborne. Obviously the power of the .91 4-stroke is sufficient. I flew about two large circles to get the trim right, I noticed some tendency to turn left which was easily corrected. The elevator was trickier, the plane is still nose heavy. Flying happily a few circles to get used to the plane was without any problem, so I started the approach to land it. First one went bad, as I have set the throttle trim rather too high, and the idle rotations of the engine where too high to allow a safe landing.

20 m before the end of the runway I gave up and started to make another circle not to ruin anything in the high grass which starts after the runway.

I trimmed down the throttle, so there will be no problem at the next approach.

 

But the problem was another one. I flew the landing curve to wide and crashed into the trees at the end of the field.

Don't ask me why, I fly on this field since one year, had for sure a few hundred flights here with different size electric aerobatics. But there is always a first time. So it happens.

The plane fell down into the little stream which is below these trees, I am not sure if the engine likes this kind of shock water cooling.

 

Two guys working on the other side of the fence helped me to get the plane back, but I managed to step to close to the water with the result that I sunk in up to the knee, lost balance and set myself more or less in. Even we are in Italy it is still a bit fresh here for a bath.  

So what happened: Half of the tail broke, but I think a repair will not be very difficult ( and it will also solve the problem being nose heavy )

 

Beside the tail damage there are a few cracks in the oracover, made by the twigs of the tree. Those can be easily repaired.

 

So in the end I have to be happy that not more happened.

 

 Now I will go and wipe the engine and turn it a few times with after run oil to be sure there is no water left inside. As we have our official season opening event on Sunday I will leave the Extra for a while and go back to my electric Sukhoi 29 size 30

VA

 

 

 

Edited By Vecchio Austriaco on 09/04/2010 17:55:12

[Tim Mackey]

Oh bad luck Vecchio

Still, glad to here that it wasnt too bad - better luck next time.

Those trees are magnetic you know!

[Vecchio Austriaco]

 Small update

everything was repaired by sunday morning but the temperature dropped 15 deg. and we had strong wind - about 40km/h - so the opening event for the 2010 season was moved to 18th. of April.

 

 

I repaired the tail by glueing it into position with thin cyano acrylate and I supported the broken area by a 5x5mm triangular balsa profile.  Also I addes a steel wire support which should help against forces which tend to brake the tail again. also it helps against beeing front havy...

 

Yes - as you can see I went too close with the heat gun during the repair action - so the white line at the bottom shrunk at one point. Will repair it only when the plane flies properly...

 

besides the obviously necessary repairs I made threaded aluminium flanges for the cowl fixing screws - and useed some M3 hex screws which I took from my son's heli spares.... so those shouldn't come out any more.

 I changed the thrust angle of the engine - added approx 2deg to the right. I will see if it runs straight now.

 While opening the cowl I saw also that one of the fuel tubes was melted - so I replaced it with a silicone rubber tube. 

 As I had the feeling that the engine gets rather hot (even the carb setting was rather rich) I made a bigger opening into the cowl next to the exhaust to improve the airflow through it.

 Also on the wheel covers I found some weak points and reinforced them around the axle inside with some 2mm ply.   

 So now I am waiting for Saturday to have the next try.

VA

Edited By Vecchio Austriaco on 15/04/2010 22:41:26

Edited By Vecchio Austriaco on 15/04/2010 22:43:31

[Vecchio Austriaco]

Back from the field, driven away by rain. But I managed to make two successful flights with my Extra and I am quite happy with it. The little improvements as described above did help, so no screw opened itself any more by vibration and also the plane flew more straight with the 2 degrees of thrust angle added. Center of gravity looks better as last time as well.

 

Unfortunatly it was a rather dark day, so the photos done by my son are not the world. But better than nothing as they are the first flight photos which didn't end in a tree.

 

 

 

Today I made my landing curves much smaller and landed rather on the left side of the runway - just to be sure to have enough distance between the plane and the trees.

 

All went well - just the engine stalled short before landing - looks like the idle mixture is too rich. I will change that and try again if the weather improves.

 

With that post I close my build diary, I am quite happy that I changed the design. Now I am pretty sure to have a plane which is a little bit different to those you find at the shelves of the shops. (But I am not alone with this design - I saw already a model which had the same design on a German webpage)

 

The carburettor extension, which I mentioned some posts above, works problem free. 

 

Also I like the exhaust pipes, they not only look good, there is almost no oil on the wings, I just need to wipe the fuselage bottom and the tail.

So I am back to IC power after a long phase of electrics.

And I don't think it will be the last one.

VA

 

 

 

[Vecchio Austriaco]

 

Even I said above that I have closed my build diary - another message. As I had a lot of fun in building this model and there was an interesting offer I am going to build another Extra. This time it will be a kit from Bettini (historical as the company closed 6 years ago) which was in the loft of a clubmate, unopened. And as usual it will be a bit larger as the previous one...

 

Extra 260, wingspan 2200. The build diary will be opened soon.   

VA

[Sheldon Holy]

Good to hear that it flies! I had the same thing on my SC (same as yours) .70fs. Different size, but the factory settings obviously wern't quite right so leaning it out about 1 turn on the low end fixed any problems. It is the best running engine i have ever had and the only time i have had deadstick is when i've run it out of fuel...

 

Sheldon

[Vecchio Austriaco]

The building diary is closed - now I can start a repair diary...

 

25.7.2010  The  weather was nice and sunny with almost no wind, the Extra 300 was flying without any technical problem - but the terrible pilot managed to bring it into a spiral stall - and the ground was too close to get it back....

 

Firewall ripped out, and also after the section where the undercarriage is mounted a "concertina" and jou can see that even Ken, the unlucky pilot, was ripped out together with his seat. (see picture)

Also the wing got its part - the wing joiner came out on the left hand side.

 

Engine seems to be o.k., even the prop survived. I will see later if the engine shaft is bent or not.

 

So instead working on my new Extra I have too look how to repair the old one...

VA

 

Edited By Vecchio Austriaco on 25/07/2010 16:58:10

[John Privett]

Ouch! Sorry to see that.

 

However,  look on the positive side,  I'm sure it could have been a lot worse...

 

[Tim Mackey]

Bad luck again Vecchio

I see the pilot is hanging his head in shame

[Vecchio Austriaco]

The wing is aready "epoxied" together, need to reapply the balsa covering and the monocote. Fuselage looks a bit sad still, but repairable. In a weeks time I will be in the air again (for how long?????)

 

Pilot: Ken suffered rather from the G-force of the impact - and I will not add a self portrait to see the shame in my face....

 

And to John: You are right - first of all I crashed in a save distance to all other human beeings on the field. Second - I selected a rather soft spot close to a little stream. I saw other clubmates where the spinner came much closer to the tail than in my case.

[Vecchio Austriaco]

Repair diary:

 

The wing got its balsa covering and is already sanded. It's just waiting for the fuselage to be in the same stage then I will apply the monocoat on both parts (hope I have still the necessary quantity...

 

The fuselage is the tricky bit. I had ro renew the firewall as most of the little square noses which fit into the fuselage came off. In the zone where the fuselage was squashed before I made inside the fuselage a second layer of all ply wood parts and did a lot of measurement to be sure everything is in its right position. The maiden flight will show if I worked correct or if the bird tends to fly into any odd direction... 

Now I am ready for the balsa covering, but I will apply fuelproofer before.

 

 

[Vecchio Austriaco]

Now lunchtime is coming soon - lets have a look what's in the oven.

That's strange - lets have a closer look

 

Today's special is baked cowl. As there were many cracks even a few pieces missing I decided to do a proper repair. First I stripped down the paint (what is still on is the original paint from the Graupner kit - they must have used some 2 component stuff as it doesn't dilute with nitro) and then I reinforced all damaged parts with glass fabric and epoxy. As usual I cannot wait - so into the oven and after 3h it should be ready

 

The remaining resin I used to fuelproof the new parts of the fuselage. But the fuselage is too big for the oven - so it hardens in the Italian sun.

[Vecchio Austriaco]

The repair is making good progress - all cracks of the cowl have been closed and smoothened with polyester filler. First color was applied yesterday evening, second color some minutes ago. The cowl will go into the oven again to be ready for the fuelproofer this evening.

[Vecchio Austriaco]

And here it is again - the Extra 300S. Not yet completely finished, have to set up the gas servo after a gear change and have to install the glow plug connections. But this is peanuts in comparison what has been done during the last 3 days.

 

If somebody wouldn't know he wouldn't see that this was a wreck last sunday.

Also Ken is in the right position again, looking with his bright blue eyes into the exiting future .. but actually he is looking to the bin bags at the end of the garage...

 

2nd maiden flight will only be next week, as the fuel proofer has to dry out properly.

 

If you ask youself what else have I done during the last 3 days - the answer is - NOTHING -  this is the advantage of being home and the family still on holiday.

VA