Electric Grumpy Tigercub

[john stones 1 - Moderator]

Yep, that looks the business, lovely job.

[Steven S]

That is coming along very nice.  My fuselage is about finished, but I haven't started on the wing yet so I'm following your build closely. 

[Dwain Dibley.]

That is an excellent job, no need to be ashamed of it ....... Plus Orange is probably the best colour in the world.

When trimming the film on say a wing, I use a sharp pair of scissors, start the cut and then run with it like using a blade, using the wood as a guide for the tip of the scissors. This will leave you a nice 4 mm overlap. You can alter the overlap by adjusting the angle of the scissors. Try it on some scrap wood, you will be surprised.

D.D.

[Chris Walby]

Thanks Ron and DD for the helpful advice + the anybody else with words of support. the new razor blade worked today and I'll try the scissors out on the C47 tomorrow.

 

Things are coming along, but still can't say I am overly happy with the quality of covering however that's just down to me! 

 

To do

• Grumpy's office and canopy
• Tail stripes
• Aileron servo plates 
• Glue all the hinges
• Control horns and clevis's
• Set control throws and check C of G
• I have a check sheet that I use on all of the models developed with the idea of no surprises for the club inspector or me come the maiden (I'll share it later on)

 

 

PS, black spinners on order from George, teach me for changing from yellow!

[Ron Gray]

We see faults where others can’t !

[dan h]

Looks great Chris nice one.

Black spinners will def look nicer

 

Dan

[Chris Walby]

Dan, I rather like yellow and the previous photos of GTC's are that colour with stripes so when sorting out the wood and other bits thought I would get everything in one go in March 2020. 4Max order placed for some more bits n bobs.

 

I prefer to have all the bits together and at hand during the building process and thus ordered motors, ESC, UBEC, props, wheels and everything else I could possibly think of including spinners. Then it dawned on me that tigers are orange (ish) with black stripes and as I had not ordered the covering film I changed my mind to orange Solarfilm (they might have run out of yellow anyway!) and the order arrived just a few days later.

 

Lesson 1 Don't own translucent covered models which are almost symmetrical in flight.

Lesson 2 Hopefully orange shouldn't be too dark a colour in any orientation and won't be flying in such an extreme manner as the EST

 

 

 

 

 

 

[Chris Walby]

Yesterday managed to glue all the hinges and finish Grumpy's office, plus cover the aileron servo covers. With a bit of a push it should be all finished by the end of the week.

 

I'll round it up with some comments from the build including problems, features and modifications that I have come across during the build.

 

[Chris Walby]

Making yet more progress with control horns fitted and snakes cut to length plus nacelle air scoops and the correct spinners. ?

 

 

C of G is a little rearward (less than 5mm) but that was with the model inverted and it drops either way rapidly unless absolutely horizontal so will try it the normal way up to see if there is a difference. Might need to add a small amount of lead for the maiden although I am not too worried as its coming out at less than 100g over target weight of 2.068Kg and won't make a massive difference. Might even try moving the RX forward and see if that gets me close enough and leave at that.

 

Must be the weight of that tail wheel ? And I really like those 4Max control horns and Model Fixing servo screws

 

 

 

  

[Peter Miller]

THat looks great. I love your pilot.

 

 

 

 

[Chris Walby]

Final chapter

Rechecked the C of G and its very close so once I have found the lead weights hiding in the car “model spares” container I’ll see if a couple make a difference.

All the control throws set are up on the TX switch with 30% expo + less on the low rates equal to Peters aileron low rate suggestion and then a bit more should I every have my bike clips tight enough!

I do have the throttles and ailerons on separate channels between port and starboard and was think of a way of selecting a motor (say 3 position), and then perhaps the trainer button to cut the selected motor. The idea would be to get +4 mistakes high cut one motor and the poke the cub with a stick….the advantage would be if it spins I have both motors available to help me should I need some.

 

Bit of a concern with motor and ESC ventilation hence added a “tablespoon” exit air scoop just for good measure to the inside of the nacelles.

 

Summary

Always worth in my book just to review while its still fresh any worthy points for this build which is essentially all standard except with electric motive power.

·         Well proven classic Peter Miller design and don’t be put off it’s a twin, no hrder to build than a single

·         Drawings available from Sarik, wood packs from SLEC (contact me)

Deviation form plans

·         Fully sheeted wing as I find it easier to build and cover plus adding decals and more damage resistant

·         Fit aileron wing servos

·         Modify the nacelle side plates to pull the ESC power cables through and keep the servo wires separate

·         Nacelle inlet and exit scoops for motor/ESC cooling – you could make a slot at the TE of the nacelle as an exit

·         Possibly move F4 so it does not clash with the ESC power cables exiting the wing

·         Talk to George at 4-Max about different Rudder and Elevator servos as there are major space issues with the supplied servos (others have used smaller case servos as per plan)

·         Thin ply plate on top of rudder/elevator servos to stop power cables snagging, can be removable or screwed down (prefer removable as I can check screws/clevis on preflight inspection)

·         Put wing servo wires in a single plug for ease of connecting

·         Incorporated the UBEC in the wing wiring as it reduces connections to the RX

·         Changed F3 to thicker ply for the bigger battery hole needed

·         Changed F1 and F2 from balsa to ply to support the battery hatch

·         Tail wheel instead of skid

 

Really nice build, nothing too tricky and possibly easier than the Ohnmen but that might be because it was built first.

 

Last thing, thanks to all that chipped in with advice and made up the +800 views and of course super special thanks to Peter for designing the GTC.

[Chris Walby]

And of course its rare for a tiger to have only one cub hence as I was building mine another club member was doing the same so enjoy the GTC pair!

 

Edited March 11, 2021 by Chris Walby

[Ron Gray]

That’ll be some sight, 2 in the air together!

[Murat Kece 1]

Yes. It definitely looks like a tiger.... Good luck with the maiden.

[Peter Miller]

They look fabulous.

 

It might not be a good idea to fly them in formation

 

[Ace]

They look awesome and look forward to hearing of successful maiden flights ?

Only been lurking/watching from the sidelines and really appreciate the time and effort in sharing ?

[Ron Gray]

2 hours ago, Peter Miller said:

They look fabulous.

 

It might not be a good idea to fly them in formation

 

If you do, I suggest attaching a streamer to one so you know which is which! ?

[Chris Walby]

Thanks to everyone who has chipped in as its always appreciated to know there are people watching. Can never quite tell but I am sure the maiden will be uneventful and it will settle down as one of the "kept in the back of the car" for use when ever there is a chance to nip up the field for a few flights (post club inspection and after the 29th of course). 

And on that subject I thought I would post the check sheet I use, if anyone wants in word format just message me). I take no credit as its just a parts copied out of various other check sheets formatted for easy use. For the GTC, there is nothing too unusual, but like the mossie and Extra Slim Twin there are quite a few mixes and servo settings to get it to do what I want.

 

   

[brokenenglish]

I've just read through this thread.

Very interesting, but I don't see anything vintage.

Strange to find it in the "Vintage" section.

[Peter Miller]

BrokenEnglish

I think that the section is Vintage, semi kits and plan projects.

 

Chris

That is quite a check list. Mind you I can see one item on there that someone (probably most people) should have checked on a regular basis.

[Ron Gray]

TBH I don't look at the sections for any posts, I just look at the topic title in my 'Latest Posts' list!

[brokenenglish]

10 hours ago, Peter Miller said:

BrokenEnglish

I think that the section is Vintage, semi kits and plan projects.

 

Chris

That is quite a check list. Mind you I can see one item on there that someone (probably most people) should have checked on a regular basis.

Peter, Surely that means vintage semi-kits and plan projects. If it were intended to mean any semi-kit and plan build, it wouldn't be in the vintage section. 

[Chris Walby]

Final post, today was the day for the maiden. Quick flight with the Carbon Yak to dial the thumbs in and battery all charged up.

Good check over by one of the club inspectors, despite my couple of previous checks I still think well worth the second pairs of eyes just to ensure everything is right.

 

Take off was straight and apart from me being overly enthusiast with the aileron stick the climb out was uneventful. Flicked to low rates and settled into a flew circuits and lowish passes with varying degrees throttle. Speed range is very good and has plenty of control and warning that you are slowing up too much (it does fly very slowly if asked). Bonus it fits in the car with the wings on.

 

Overall I would recommend this as a not too difficult build and very nice flying model, not to heavy or too light. ground handling is good. Running 4S3300 gives 5 minutes and 50% lipo left and will roll an loop with style.

[Peter Miller]

I am so happy that you had a good flight and enjoyed it.

 

Wishing you many more.