Gloster G40 RBC Kits

[Ton van Munsteren]

Tony,

 

Sleep one night over it there are some more options.

 

Have a look at this set its metal with 4mm legs and would do the job just fine for only € 99.-

http://www.rbckits.com/shop/index.php?_a=viewProd&productId=466 

 

Ton

[TonyS]

Thanks Ton,

I know that you'll know the answer to this but, will adding in all this stuff make the kit too heavy... and where on earth should I put the gas cylinder - I assume that I have to be able to get it in and out to replace it when it runs out of air... 

I'm also wondering how to fit the doors on the u/c bay. Will this simply connect to the u/c strut or is that yet another servo. I'm guessing the all-up weight will be around 20Kg if I carry on like this..... 

 

Sorry about all the questions but my head is spinning. I'm also wanting to fit flaps (another first) and am trying to work out how big they need to be, where to put the servos etc etc..

I really enjoy the challenge of it all but maybe this is all a bit to much for my amateur skill level?

 

 

[Ton van Munsteren]

Tony,

 

Don't make it to difficult on yourselve , better a model flying just super with a bungee start.

Than one endng up on the attic halve way build.

 

Its not the easiest models to go with retracts and flaps, specialy when its all new to have a go at.

 

Ton

 

 

 

[TonyS]

Don't worry Ton,

Whatever I decide to do I'll finish it.

I may just go with flaps on this one then try retracts on the next one.

T 

[Tim Mackey]

That set looks a lot like the spring air stuff - a bit cheaper, but at todays exchange rate still almost £90

The air tank is mounted anywhere that suits, and does not need to be removed once fitted - re-filling is via an externally mounted small "fill valve" using a pump

[TonyS]

OK that helps.

Does that mean I'd need to buy a pump as well Timbo?

T 

[Reno Racer]

Tony,

 

A|pologies for the late reply.

 

I used Spring Air 602s, although you need to widen/replace or doctor the orignial retract mounts, particulary the nose wheel; as you know there is not alot of space here. I opted not to steer the front leg and ommitted the rudder (although I wasted  a few hours ensuring she ran straight doing ground runs!).

 

I fitted flaps from the fuse TE of the wing up to the ailerons and mounted a slim glider wing HITEC servo (can't remember the type) into the wing - It does help if you opt to use the proper scale doors, although you need to build up the underwing budlge - you can hide a servo in here too.

 

See here: (Science Museum)

If you order the Spring Airs from the manufacturer, they take an age to arrive - Hobby King do some good quality all metal retracts, these are slighter smaller then the 602s and will fit:
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=8346

and they cost about £50

 

I also binned the balsa covering in the wings and stabs and used Mick Reeves pro skin - admittidly I got carried away trying new methods,

 

If I built one again, I would just build as per the instructions and just glass the whole thing. I would also add more power, propably a lander 90mm fan - there is room for a 3S lipo each side of the intake of at least 5800mah; I currently uses these on a 90mm lander fan:
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=9932

 

Turnigy 30/40C 5800mah 3S lipos, $50 (£35) each!!

I also found the only place for all the electronics (Rx, retract sequencer etc) is the top deck under the canopy which is quite small. You can put some stuff (retract switch etc) at the side of the fan, which you can only access when you take the wing off.

 

I also cut the canopy so that I could have it slightly opened - This became a right drama in tyring to make a bad job look good. I would just fit the canopy as a 1 piece item.

 

Overall, once I had worked out that some CNC peices were wrongly marked (by studying the plan and CD of build photos for ever!!), I really enjoyed building the G40. The result is a really strong, traditionally built EDF which when glassed and jazzed up looks as good as any turbine jet. moreover, Its completely different from all the other boring and predicatable EDFs out their.

 

I'll stop now before I get on my soap box again about the lack of good quality turbine-like 90mm EDFs......

 

Regards

[Tim Mackey]

Hi Tony... the tank can be filled using any simple pump such as bicycle pumps, car foot pumps, 12V tyre pumps etc etc. Special dedicated pumps are available but I have never found them necessary.

[TonyS]

Right guys - back to the kit..

I left the next step in the instructions - sheeting the fuse - until all the electrical bits (servos etc) have arrived as I want to check where they'll be going before closing up.

Skipping forward I decided to make up the elevator/stab assembly as this seems pretty much a stand - alone exercise. Turned out to be not so easy after all.

 

First job was to pin the helpformers to the plan:

Great. Then I had to take them off as I realised that the bottom skin needed to be cut to fit into the notches at the front. So, I unpinned the helpformers, traced out the skin per the plan then re-pinned the helpformers. I carefully cut out the skin (1.5mm sheeting) and laid it on the formers - the instructions dont tell you that any shaping per the plan needs to be done after the elevator is made up. They aren't straight lines. Now my sheeting doesn't butt up against the end helpformers....

Sorry about the blurry pic.

Next I cut out all the internal formers, slotted the whole lot together without gluing and laid them on the helpformers to test the fit...

Note that the internal formers and the helpformers don't line up..not a massive problem until.....

 

you get to the tip 

The skin lines up to the helpformers which in turn line up with the plan but the internal former assembly is longer than shown so now my skin is cut too short and I've wasted the 1.5mm sheeting and the time gluing it sanding it and cutting it..

I may be me but I'm beginning to despair of this kit's instructions. Why didn't it say cut the skin per the plan but don't shape and leave several mm extra at each end !

I wonder if  kit builders give the kits and instructions to a pretty average kit builder and see what they make of them. It would be so easy to add a few helpful notes here and there. 

Oh well, back to the bench to re-make the skin (and back to the hobby shop for some more balsa !!) 

 

[TonyS]

Just in case everyone thought I'd forgotten the poor old Gloster.....

 

I've built up the elevator now and skinned the top. Forgot to take pics sadly (got too involved).

Not too much drama. When it came to shaping it I drew round the plan with tracing paper

then sat it over the built up part.

I then marked the outline onto the part using a spike...

I then had to create a sandwich of two shaped tip blocks (to give depth) and fix these onto the ends. In typical fashion the parts are not marked correctly. If you use the ones suggested you'll find that there seems to be one larger than the others..

After some head-scratching I worked out that you need two large tips for the base of each side and two smaller ones for the tops. The mistake in the plans is that one of the smaller ones above is actually one of the two tips needed for the rudder. I recommend you cut them all out and then work out which is which by comparison with the plans.

A bit of whittling later

and , hey presto...

Only when I'd built this and compared it to the Yak 23 did I realise how big this plane will be when it's finished. It's amazing what a difference 9" makes i.e. 50" wingspan compared with the Yak's 43" ......

 

 

[Dusty]

Tony... getting on there, wow is it xmas at your house, quite a few toys going on there with this and the FPV etc etc lol!

 

Thats looking great!

[TonyS]

Too right Dusty!!

What a Christmas I've had this year. Never before and unlikely ever to be repeated (my business partner bought me a Blade 400 3D to play with too!!!)

 

Sadly, back to work tomorrow but never fear...I will be rushing home to see if the postman has been with some more bits. Then my wife has to pop into town for some more sandpaper, that's if she can stop playing with the ironing board cover I bought for her.... tut!  

 

This Gloster is a big boy - should look great in the air. (What do you think about a bit of air to air video of it from a FPV chase plane ...?)

 

 

[Dusty]

 Ya  thats a big balsa EDF, looks great too " classic jet age"

 

Sheep you got a helicopter too!  Tony you got some stuff there to keep you busy well into the new year, I shall be watching your many threads of your projects!

 

I got stuck with a piece of foam and had to buy the wife a puppy..

[TonyS]

I've seen your " piece of foam" and it's a beauty! Got to ask where you got the idea for modding access to the fan. I like that kind of thinking. Careful with that puppy. They love to chew stuff and I'd give your Mirage about 20 seconds if it got Fidos attention.

[Dusty]

Tony the idea is in Jepe's manual that contains 100's of photo's for the build. I dont like the idea of having no access to the powertrain as nothing is perfect and things break, wear out or fry up.

 

"Pugsy" is still playing fetch and learning to use the doggy toilet, not being taught to chew daddy's model plane made out of foam, its stored in safe keeping when I am not about just incase she fancies a "miragebar".

[TonyS]

Having a bit of a nightmare with the Gloster at the moment.

 

Progress has been halted on the fuselage while I wait for deliveries of leccy bits and work out where everything is going to go before finishing the sheeting.

On this basis I made up the elevator assembly which all in all wasn't too bad. My progress on that however was halted due to a lack of, would you believe it, sandpaper.  (And it's snowing like Billy-O so no chance of popping out for some today. I then began the wings and realised that without the servos (come on BRC) I wasn't going to get too far with them.

I therefore thought I'd make up the rudder which looked a piece of cake. How wrong.

 

Apart from gluing my fingers to the assembly then to my other fingers and finally my scalpel, I managed to glue the skin to the wrong parts and trim it to the wrong edges. Awful.

 

I can only think it was overconfidence.  Looking back over the instructions however they really are brief. There are 6 pictures - one of which shows the finished piece - and 3 lines of instruction. This wasn't enough for my limited experience I'm afraid. Anyway I'm sort of managing to fix it slowly but the build time is probably 3 times what it should have been. 

 

Conclusion - the Yak-23 instructions were a lot more comprehensive and this kit assumes a reasonable level of previous building experience.... 

[TonyS]

Quick question re the power set-up on this model.

 

I've received my motor today - A HET Typhoon 600-42. The HET website recommends a 7S set up for this motor in the Wemotec Midi-fan.

Sounds daft but to get 7S I need to connect two batteries in series. Each one will be positioned on opposite sides of the ducting in the fuse so balance becomes an issue if I link a 3S with a 4S. Unless of course the 3S is of a higher capacity (thus getting the weight more even). I'm thinking a 3,600mAh 4S on one side and a 4,500 3S on the other....

Can you mix capacities like this? 

[Tim Mackey]

No. There are some mixing scenarios which are quite OK, but this is not one of them.

 

[Tim Mackey]

Sorry, that was too brief. Rather than repeat what many peeps have already stated in other forums and the like let me rob from a few which I happen to agree with ( there is a lot of mis-information out there too of course.)

The following are generally acceptable, with some provisos as mentioned
1. Connecting different voltage packs in series. This is a common practice used to achieve high-voltage packs for larger planes, such as a 6S and a 4S connected together to make a 10S.
2. Connecting same-voltage, but different capacity packs in parallel.  Not really recommended but theoretically, there shouldn't be any technical reason why it wouldn't work, as long as you keep your current draw below the combined capacity of the two packs.

3. Connecting different capacity packs in series. The worst thing that can happen here is the weaker pack gets damaged or destroyed by being overdrawn. If care is taken to base decisions on the weakest link in the chain, there's no technical reason it won't work.

Now this is where I see a problem with your setup - powerful EDFs will be pulling high currents - possibly higher than the smaller pack can handle, but also remember that your total capacity can only be based on the lowest capacity pack, in this case 3600mahr. Another potential issue ( dreadful pun non intentional ) is falling voltages, the stronger pack possibly "outrunning" the weaker and allowing the smaller pack cells to get below minimum threshold.

 

In almost every case of mixing different packs, its the norm to recommend that you use identically matched cells throughout.

 

This thread here may also explain things further

Edited By Timbo - Administrator on 06/01/2010 19:20:45

[TonyS]

Thanks Timbo,

So what we're saying here is that to get a 7S setup I need a single 7S battery or POSSIBLY a 4S and a 3s but with the same capacity...? 

Maybe I should just go with two identical 4S batteries of the same capacity as the motor will run happily on 8S.

 

[Tim Mackey]

Yes Tony. If the fan and motor are happy on 8S then I recommend that. Try GC for the packs.

[TonyS]

Hmmmm.

 

The age old problem with high output set-ups with an added twist.

2,000W quoted from an 8S set-up for this motor / fan combo.

A  4,000mAh pack drawing 2000/29.6V i.e. 67.6A would last 3.43 mins at WOT which albeit not brilliant should give 4-5 mins plus with some sensitivity on the throttle I guess.

 

Trouble is I can't find a battery of 4,000mAh thin enough to sit inside the fuse between the sheeting and the intake tube. Max I can realistically go to is c 30mm wide.

 

 

 

So, I need a long thin 4S LiPo of 3,700mAh +...........

 

Anyone know of such a beasty......? 

[philfly]

How about 4 2s batteries? That would give you 8s and can be distributed around the fuz

Connecting all up would be a nightmare but they could be connected permanantly into pairs, then leaving a y lead to connect the '4s' packs together?

Edited By philfly on 07/01/2010 12:52:40

[TonyS]

Philfly,

Will mock up some 2S packs and see what that does.

 

Tonight I set about the wings proper. What a pain this is turning out to be. Apart from the usual numbering fiasco for the parts, parts on the plan not in the pack or in the build photos etc etc, the cut pieces don't line up with the plan, and the fronts of the ribs, when it's all slotted together don't run true so some fiddling about packing is required I think (unless the leading edge is supposed to be concave....?)

 

Not a happy bunny... 

[philfly]

Any news Tony? how are things going?