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Seagull 80" DH Chipmunk

A bit of light relief

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Danny Fenton08/03/2019 21:17:56
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9066 forum posts
3928 photos

The result of the thiner section and using medium balsa meant that the structure was a little too flexible. So I had to add the diagonal braces. The opposite side runs the opposite way, so between the two we have a crossed structure. This has stiffened the whole lot up significantly. If I really wanted to take it further I would use dope and tissue/nylon/silk as they impart even more strength. But as I am using film this is as strong as it will get. Iron on film adds nothing to the structures strength.

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56g  so far (original 180g) and each pin weighs a gram!!

Cheers

Danny

P.S. There are some really sattisfying to produce chamfers amongst that lot smile p

Edited By Danny Fenton on 08/03/2019 21:19:48

Edited By Danny Fenton on 08/03/2019 21:20:56

Danny Fenton08/03/2019 21:24:16
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9066 forum posts
3928 photos

You might be right embarrassed........ Shall I stop now, drop this in the bin, and accept 1/2 lb of lead in the nose?

If it flies well at 11 1/2 lbs it will fly even better at 11 lbs

Cheers

Danny

Denis Watkins08/03/2019 21:51:22
3611 forum posts
166 photos

Woe Danny, this quality of work and logic is " top drawer " and read by many

Don't be put off by trolls, just ignore

Ron Gray08/03/2019 22:17:13
1407 forum posts
358 photos

If you were only going to save a couple or few ozs of nose lead then not worth the effort but at your rate you will be looking at a significant amount more than that so a job well done.

Danny Fenton08/03/2019 22:41:07
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9066 forum posts
3928 photos

Thx guys, i won't go mad, but if you had picked the tailplane up you would have been shocked too. A hundred gram saved at the tail is several hundreds up front.

If i can easily do bits and pieces to tidy the model up I will.

Cheers

cymaz09/03/2019 05:40:17
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8451 forum posts
1160 photos

Master class in building....top job yes

Low pass Pete09/03/2019 06:36:51
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205 forum posts
118 photos

Good day everyone. I have just completed and flown my Seagull Chippy. Mine has an OS120 4 stroke for power with a just Engines turbo Header for exhaust.

I balanced her as per plan. Virtually no trim required on test flight at all. Looks to be a super flyer and only needs the power of the 120 very little of the time. I found no issue at all with weight of tail but I suppose if going electric it may well be more of an issue.

I am impressed with the flying qualities of the aircraft and deploying the flaps brings virtually no trim change which was very surprising.

The aircraft will fly nicely at a more scale speed.

Best Regards

Peter

Danny Fenton09/03/2019 07:54:18
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9066 forum posts
3928 photos

Cheers chaps. Good to hear Peter, that confirms the thoughts of the guys on RCGroups.

What weight did yours come in at, and where is the C of G, if you don't mind me asking?

The fact that the model is electric, has no bearing on needing to be light, the lighter the model the slower it will fly.

Cheers

Danny

Low pass Pete10/03/2019 06:06:11
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205 forum posts
118 photos

Hi Danny.

C of G on mine is set as per build instructions (130mm). Have not actually weighed her but she needed no ballast. Receiver battery was mounted on the plate just rear of the fuel tank. I swopped the kit fuel tank for a Dubro one. Also I have a small 2s Lipo fitted to supply the landing lights with an electronic switch.  Otherwise as per kit. save for a repaint on the kit supplied pilots to improve their look.  They were not the best but do look better now.

 wink

Chris Bott also has a Forum post ref C of G by the way.

Cheers

Peter

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Edited By Low pass Pete on 10/03/2019 06:06:52

Edited By Low pass Pete on 10/03/2019 06:08:29

Edited By Low pass Pete on 10/03/2019 06:11:45

Rich too10/03/2019 08:00:43
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2876 forum posts
1046 photos
Posted by Wingman on 08/03/2019 21:12:33:

Oh dear Oh dear! What a kerfuffle. It's a Seagull ARTF - they are all good flyers straight out of the box in my experience and almost Hangar 9 quality and it's to be used for flying only comps you say - it's a chipmunk so sedate to moderate flying is the order of the day and weight won't matter as regards a pound or so - looks to me like OCD is creeping in heresmiley or is it a guilty conscience for not building a competition model from scratch??wink

Edited By Wingman on 08/03/2019 21:14:52

My.thoughts too initially. However, if it saves 1/2 pound of lead in the nose it is absolutely the best thing to do. Well done to Danny for putting the extra work in - I would have taken the easy option.

Danny Fenton10/03/2019 09:04:02
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9066 forum posts
3928 photos

Thanks Rich, I was very tempted to take the easy route. Chris Bott and I fly at the same club, and have identical setups motor, servos radio etc. So we will no doubt have a go on each others model so we will see what a difference it makes.

Apart from 3 days extra work, i am pleased with the outcome.

Cheers

Danny

Danny Fenton10/03/2019 10:10:30
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9066 forum posts
3928 photos

Spent a very pleasant couple of hours last evening with pizza and beer setting up my new X10 with Chris Bott.

We flashed my X10 to the latest firmware, and then we copied Chris's setup from his X12S to my Companion software, I then copied the model into my Tx, the software realised the Tx's were different and converted the file. I then copied the config to the Tx. The reason you do it this way is to avoid copying Chris's Tx callibration.

Some of the sensors, Volta, Amps, Alt etc needing re-discovering but after 30 minutes I had an identical config to Chris's. Awesome radio.

Chris makes these sensor boards, based around an Arduino processor, he also has designed this really nifty power board which allows dual power feeds for your Rx, if one fails the other will take the load. A clever cahp is Chris!

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Chris has an article on the sensor board coming up in a future issue of RCM&E, should be good! Chris is helping to put the "E" back in RCM&E, well done Chris, and thanks!

Cheers

Danny

Danny Fenton10/03/2019 17:05:04
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9066 forum posts
3928 photos

Okay was it worth three days effort? Maybe not, but it is done, I will cover the bits and move on

I was going to use Robarts with a recessed hinge and shrouds, hence the slots on the left elevator, but I climbed back from the brink, and fitted the fluffy mylar hinges

All good fun, which is all that matters.

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Cheers

Danny

Martian11/03/2019 18:15:03
2147 forum posts
1031 photos

Thanks for your thoughts and insight

Danny Fenton12/03/2019 11:44:58
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9066 forum posts
3928 photos

Feeling a little under the weather, probably another cold.... sigh. Anyway it has meant my enthusiasm has waned a little.

Anyway I hate iron on covering, so thought I would get that nasty job out of the way. Not as keen on Oracover as others it seems, but it is done now.

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weight difference is interesting, if you consider that the distance from the tailplane to the C of G is 3 times the distance to the area where weight could be added to the nose. therefore the saving of 100g equates to 300g of nose weight removed, plus the 100g lost at the tail. So a 400g saving overall. I think that will alter the flight envelope noticeably, but a comaparison to Chris's will tell us.

Cheers

Danny

McG 696912/03/2019 12:11:11
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2475 forum posts
976 photos

You 'll get well soon now, Danny.

Now that the nasty covering job is behind you... yes

I suppose you're going to choose for RDS servo installation for your ailerons now as well? ... angel

Cheers

Chris

Danny Fenton12/03/2019 12:14:58
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9066 forum posts
3928 photos

Now there is a great idea....... but no I need to get back to the fury

Cheers

Danny

Danny Fenton14/03/2019 18:37:22
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9066 forum posts
3928 photos

This is a first, radio, esc and servos in the fus before the tailplane is on! ah well seemed easier than bashing the tail on the walls/ceiling

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This is one of Chris Botts telem units. There will be an article in RCM&E about making one of these, I cheated and got Chris to do mine. He even designs the circuit board! Anyway this gives, volts, current Mah consumed, cell voltages even altitude. Clever chap is Chris.

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Here is the Rx in the model, it sits plugged into one of Chris's dual power feed boards, the board accepts power and feeds it directly to the servos not via the Rx, if you need to disconnect the Rx it just slides back. All the servo wires remain attached to the power board.

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I simply copied Chris's entire Chippy file into my new X10 via Companion, and everything is all set up, sticky throttle, aileron differential etc etc.

A question, I guess for LPP, how did you free up the wing tubes, they are as stiff as anything on mine and Chris's Chippys?

We have sanded the tubes in the wing, and it has got better, but still too stiff to get the model apart easily. I had to pry my wings off with a steel ruler wedged between the wing and the wing root fairing!

038.jpg

Cheers

Danny

Chris Bott - Moderator14/03/2019 20:26:45
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Danny. One quick look at that screen shot above and I see a programming mistake. Somehow we've ended up with some flap compensation with the wrong source. The + line just below CH3 is adding to the elevator, but it's sourced from rudder! Thankfully the amount is zero % so it will have no effect.

Needs fixing though.

Danny Fenton14/03/2019 20:41:04
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9066 forum posts
3928 photos

Well spotted Chris, yours is wrong too then

Just laser levelled the model with the wings attached, aligned to the wing tips, and then the horizontal stab. a little sanding to get it spot on, then some epoxy to fix in place.

039.jpg

Cheers

Danny

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