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Hangar 9 Sopwith Camel

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Tim Mackey24/07/2009 08:42:53
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Right. With the flyfly hawk finished and then er...re-kitted - and a few other odds and ends finished off, the Camel finally made it to the assembly line a week or so ago, so heres a sort of build blog.... but it wont be complete for a number of reasons - mainly due to it having a sound system installed at a later date, and that particular part of the whole project will be the subject of a magazine article, so will not be shown on the forum until after publication. However, plenty of other stuff to show and discuss, and I am already in need of a bit help, and I am only just started! 
I should say that I have made a few design changes as will be shown later.
 
                 Heres the "box art"..... pretty looking model huh
Specs as follows...

# Wing Span: 61 in (1549mm)

# Overall Length: 44 in (1118mm)

# Wing Area: 1288 sq in (83.1 sq dm)

# Flying Weight: 7.5- 9 lb (3.4-4.1 kg)

# Engine Size: Glow version: Evolution .61 2-stroke; 91 4-stroke 

 # Radio: 4 channels w/5 servos

 # 14 X 8    prop.

 Originally, mine was to be powered with 4s2p LiPo and a 1000watt+ 400K/v Turnigy outrunner - both of which were purchased early last year, and bench run for power testing. Now of course the Camel is a WW1 biplane, and was never exactly renowned for its top speed...or indeed general handling manners.
 
I like a scale model to fly at scale speed, and a bit of research showed that most WW1 birds had a prop to wing size ratio of around 25 -30%, and often flew flat out at only around 2 -3 times stall speed, which I am guessing is about 30 -40 MPH. This gives a top speed of approx 120 -120MPH. Now with that huge radial cowl masking off a fair bit of it, a nice large diameter prop would also be in order. To get a scale like speed, I calculated that 8” pitch or so X 16" diameter at about 5500 - 6000 RPM would be on the money, as the model is around 1/5th scale.
Pitch speed ( theoretical only due to drag, slippage and other factors ) is calculated thus....

RPM X Pitch ( in inches ) divided by 1056......this gives speed in MPH.

6000 X 8 = 48000

48000 / 1056 = 45 MPH. Bit faster than scale...but I do have a throttle!

A few static bench runnings of the powertrain showed decent figures of  5500 RPM, 40Amps, and some 600 Watts on the 6000mah 4s Lipo pack, as the large packs were holding very good voltage under a comparatively light loading. I expected the final AUW to come out at about 9.5lb, so this gives approx 63Watts per lb, which may bea tad low . Right, I shall leave it there just for now, and be back with the second bit in a short while…breakfast beckons.

Edited By Timbo - Moderator on 24/07/2009 11:39:43

Edited By Timbo - Moderator on 06/09/2009 23:17:12

Brian Parker24/07/2009 09:05:54
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Looking good so far. Do you have a publication date?
Tim Mackey24/07/2009 10:03:07
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No not yet Brian - thats down to our esteemed Editor and his bro
As I say of course, the mag piece will be concentrating on the sound system installation, and as yet I have not received the module from the suppliers... 
I shall be posting pictures and details in a little while of the motor and battery installation method I used... quite different to the norm
paul@scc24/07/2009 10:37:44
164 forum posts
Hi Timbo
Looking forward to this. Hope to have one of these in the hangar one day.
 
Benidini or Model solutions for sound?

Tim Mackey24/07/2009 10:52:53
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Model Solutions of Canada.... sorry cant say too much about the sound system on the forum until after the mag is published
Tim Mackey24/07/2009 11:32:59
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OK, that was yummy - a bacon and egg baguette, with freshly brewed coffee always hits the spot .
My research into this kit also threw up a few concerns about both design, and kit quality - surprising really as I had always believed that Hangar 9 had an excellent reputation in this area.  Amongst other things, two in particular stood out.

1)      The integrity of the Cabane struts alloy tabs

2)      The additional weight required up front to get the COG right.

Now the balance issue is to be expected I guess by virtue of the very short nose. It was this factor, amongst others, that prompted me to change direction on the power pack. Several internet forums showed people trying all sorts of methods to over-come the need to add tons of lead in the supplied ballast box - including chopping great holes in the firewall and pushing the batteries through into the cowling area, to fitting huge radial OS engines, and large petrol motors. Neither of these appealed to me, so I started thinking of alternatives, and decided that A123 ( M1) cells would be a way to go - especially if I could figure a way to get them right up the front within the cowl itself. Strong as it is, I didn’t fancy fixing 10 ( 5s2p to help the balance issue and provide good duration ) directly to the cowl, and besides, when it came to trial fitting them “radialy” around the perimeter of the firewall, there was insufficient clearance for the dummy radial engine- an essential part of the model to my mind. I then designed the following. By dremmelling back the corners of the front face extension box, I could just squeeze the required 10 cells in with the ends pushed up against the actual firewall, and arranged as shown around the motor stand offs. Using the M1s also meant fast recharge times, and no need to access them for removal each time I charged. As the ends of the cells would be potentially exposed to metal studding and washers etc, I cut a rubber gasket to insulate things which was slipped over the studding before the batteries were fitted. I obtained 10 x cells from an ebay seller, which turned out to be used cells - I suppose I should have known they would not be new, as they cost approx 4.50 each…..compared to around £10 normally. Testing the cells showed a couple were down a bit during balance recharging so I undid the 5 s packs I had made, and seprated them all back to individual cells. I made up a single cell holder, and cycled each cell 5 times until things levelled off to reasonably good level. I then paralled up the cells, using the best and worst cell as partners, working down to the two closest matches IYSWIM. These paired off batteries were then arranged into a 5s configuration, with balancing wires attached to each pair, so that I will just charge as one large 5S pack of 4.6A capacity. Of course to do this at the field with fastest charge time requires a hefty charger and PSU capable of delivering 20A and 18V ( 360 watts+ ) and even my I-charger 1010B+ can only do 10A and is limited to 300 watts, so recharge times will still be around 30 minutes.


 





Edit - due to higher than expected weight, and a miscalculation on flying speed, I have upped this to 12 Cells ( 6s2p )

Edited By Timbo - Moderator on 24/07/2009 11:42:52

Edited By Timbo - Moderator on 06/09/2009 23:19:21

David Ashby - Moderator24/07/2009 11:56:05
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You've sure done your homework Tim, look forward to seeing the Camel progress
Klippy24/07/2009 11:57:32
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Nice attention to detail, can't wait to see more
Myron Beaumont24/07/2009 12:18:12
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Timbo
Just looking at the spec. & comparing it to my Puppeteer (same span )-  more or less the same configuration ?
It weighs 7 lb exactly (dry weight ) - SC 52 Fst  fitted with a 13 " prop .
Just wondering what you expect your AUW to be with sound system / fire extinguishing set-up  etc to be . Don't think it will glide too well but on the other hand of course you won't have any dead stick events will you ?.Will it keep cool with all those lekky things up front ? & where is ( are) your ESC ('s )?
PS  Have you gone from sticky buns to proper food ?
G-umpy ( a bit poorly ) & good weather forecast for tomorrow
Tim Mackey24/07/2009 12:19:10
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Thanks guys, but now the trouble starts.

I then ran into the first very annoying hitch. I had completely missed the fact that the front cabane struts were attached with Allen head socket bolts which were to be screwed into blind nuts already fitted into the sides of the fus. These had to be inserted from inside the cowling area of the front of the model… right behind the end cells of the top battery pack.  I had to undo this battery, cut the balance leads off to allow removal and gain access to the very awkwardly positioned holes. Even then getting the small screws into the pre-marked holes was difficult - made even worse by the fact that all the supplied fittings and screws are imperial sized not metric - so I had to go out and buy a set of imperial Allen keys. The socket head of the screws is really shallow, so getting good purchase on the screw was difficult - and to make matters worse, the blind nuts were all clogged with fuel proofer or epoxy, so much so, that the screw just would not start. Pushing as best as I could to get things started, I then heard and felt the horrible “Plop” as the darn nut fell off … to be heard rattling its way around and down inside the cheeks of the frontal area.. I was left with no alternative but to cut an access hatch in the cheeks in order to sort something alternative. It turned out that every nut was the same! - so I ended up removing them all, and substituting my own. Fitting the cabanes is supposedly covered well in the otherwise reasonable manual, however, after struggling for literally hours to get them fitted, trial fitting of the top wing proved impossible. Turns out, that there are very small differences in the strut lengths which make all the difference to how the wing fits - or doesn’t in my case ! So, off with all the battery cabling again, and more struggles to remove the struts. Due to absolutely NO markings on the items at all, it was nigh on impossible to ascertain which went where, so more hours and hours of internet research uncovered others had experienced the same issues. Horizon Hobbies had even posted a website update bulletin apologising for an error in the manual which actually illustrated the WRONG way to do it, and then posted a later website bulletin with corrections……but it turns out this was wrong also! Arggh !!
3 times I removed and re-arranged the struts, measuring carefully to ensure that I had a handed pair for each set ( the difference being only a few, but crucial millimetres ). Finally thinking that I had it sorted, the struts were re-fitted ( new socket head screws needed by now as the ends were getting badly rounded…...as was the key).
The battery was again re-assembled and confidentally refitted, and wing tried again.
I don’t believe it - still wrong!
Seems no matter what I try, this lot does just not want to marry up. A slight bending of the front port strut got these two lined up with the wing mounting holes, but the rear port strut is still a country mile off. The thought and frustration of having to remove everything again was too much at the time, and I went to bed very disgruntled, annoyed, and pretty much ready to abandon the whole darn hobby - that’s how mad I felt.
2 days I had spent messing about with this lot.
 
Why oh why are we expected to put up with such shoddy instructions and inaccuracies - and this from a model previously reviewed in the magazine some time back, and no mention of this, or several other issues at all. I bought this kit partly on the basis of that review, expecting Hangar 9 to dispel my annoyance in general with so called ARTFs, but so far, I was not a happy bunny. At the moment the build is on hold until I get a bit more patience back - probably via another session up the big rock flying something that does work.
Here’s the current scenario on the darn cabanes. Any ideas gratefully received.
I have now used up the entire websites stock of angry icons, so the next instalment should be full of happy ones


Tim Mackey24/07/2009 12:22:43
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Posted by Myron Beaumont on 24/07/2009 12:18:12:
Timbo
Just looking at the spec. & comparing it to my Puppeteer (same span )-  more or less the same configuration ?
It weighs 7 lb exactly (dry weight ) - SC 52 Fst  fitted with a 13 " prop .
Just wondering what you expect your AUW to be with sound system / fire extinguishing set-up  etc to be . Don't think it will glide too well but on the other hand of course you won't have any dead stick events will you ?.Will it keep cool with all those lekky things up front ? & where is ( are) your ESC ('s )?
PS  Have you gone from sticky buns to proper food ?
G-umpy ( a bit poorly ) & good weather forecast for tomorrow
 AUW willbe at least 9lb I reckon. Most bipes dont glide anyway in my experience, and with the flying wires etc this will be pretty draggy I am sure. The esc is tucked up under the lower stand offs, but I dont anticiapate a lot of heat in the front TBH - the batteries, motor, and ESC ar all well over spec, and will likely not get much more than very warm....which is good, cos batteries like warm.
The proper food was followed by a choc bar
Danny Fenton24/07/2009 13:21:19
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Arghhhh Timbo, sounds like you have taken on a monster! My sympathies mate, these bipes look great but they are sometimes a bag of trouble, and get the incidence wrong and you end up with a very poor flying model indeed. Some ARTF's seem to drop together sweet as anything. The best I have ever built being the Seagull Sea Fury which is still a joy to fly, now on 6S2P and a massive 10lbs (still lighter than Shauns IC version but don't tell him that). But that is perhaps the subject of another thread.
 
I completely agree with you, how could this have been reviewed without this snag coming up, we trust the magazines to give us an honest assesment, by all means give the manufacturer a chance to respond before publishing if they wish.
 
Can you show any pics of the cabane assemblies? is it the holes in the fus that are wrongly alligned? are they 4 seperate struts?
 
Anyway hope you can wrestle it into submission soon.......
Cheers
Danny
Tim Mackey24/07/2009 13:28:34
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I will post another piccy or two in minute...just taking a rain shower break from cutting the lawns. it cant be the holes /slots in the fus that are "wrong" as these are prefitted / laser cut into the ply sides etc.
I still suspect that somehow, the wrong struts are in the wrong positions, but having tried just about all the possible configurations none seem right. I think what I may have to do is get the bottom wing done and fitted to the fus - at least this should be correctly aligned due to a large carbon spar et al. Then I will fit the interplane struts to the lower wing, and fit the top wing onto these interplanes. This at least should position the cabane strut holes in the correct position...then "all i need to do"  is keep fiddling and changing around the cabanes until they line up with the wing holes.
If that doesnt work, then its out with the lighter fluid
I wouldnt mind quite so much if it wasnt for the extremely awkward positioning of the front strut mounting system...why they couldnt have just altered the lower tabs to fit across the lower turtle deck area and bolt down from the top, beneath the removable hatch, is a mystery to me.
Decent, deep socket head metric bolts would have also helped









Edited By Timbo - Moderator on 24/07/2009 13:46:14

Ultymate24/07/2009 13:40:25
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Posted by Danny Fenton on 24/07/2009 13:21:19:
Arghhhh Timbo, sounds like you have taken on a monster! My sympathies mate, these bipes look great but they are sometimes a bag of trouble, and get the incidence wrong and you end up with a very poor flying model indeed. Some ARTF's seem to drop together sweet as anything. The best I have ever built being the Seagull Sea Fury which is still a joy to fly, now on 6S2P and a massive 10lbs (still lighter than Shauns IC version but don't tell him that). But that is perhaps the subject of another thread.
 
I completely agree with you, how could this have been reviewed without this snag coming up, we trust the magazines to give us an honest assesment, by all means give the manufacturer a chance to respond before publishing if they wish.
 
Can you show any pics of the cabane assemblies? is it the holes in the fus that are wrongly alligned? are they 4 seperate struts?
 
Anyway hope you can wrestle it into submission soon.......
Cheers
Danny

 To be fare to H9 it does'nt necessarily follow that this fault on the cabanes was present on the other review kit and Tim has said he's not 100% sure the struts are in their correct positions or not or if indeed there is any variation between them

Edited By Ultymate on 24/07/2009 13:41:09

Danny Fenton24/07/2009 13:40:52
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Lets hope it doesn't come to that. I wouldn't be too quick to say that the laser cut ply can't be wrong LOL
 
Yes your idea of getting the top wing in position without the cabane and then using it as a jig sounds good, the only trouble is the wing struts wont control the fore and aft movement of the top wing so it will still be a little floppy.
 
Before you break out the lighter fluid, bung it my way!
 
 
Tim Mackey24/07/2009 13:52:13
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Upon trawling around the internet over the last few days ....it  seems that quite a lot of people have experienced these issues... so doubt its a one off.
In my expexerience, many reviews are woefully short of criticism - not the mags fault of course - but someones !
Tim Mackey24/07/2009 13:54:58
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Posted by Danny Fenton on 24/07/2009 13:40:52:
Lets hope it doesn't come to that. I wouldn't be too quick to say that the laser cut ply can't be wrong LOL
 
Yes your idea of getting the top wing in position without the cabane and then using it as a jig sounds good, the only trouble is the wing struts wont control the fore and aft movement of the top wing so it will still be a little floppy.
 
Before you break out the lighter fluid, bung it my way!
 
 
 Yep realise that, however, if I let it "scissor" forwards or backwards to at least try and align it with hopefully one pair of struts, that should help to sort out the alignment of the other pair IYSWIM
Brian...if your short of something to do, you could always come over and help be burn it - sorry - build it -  An experienced builders eye like yours may help a lot.
Kelly24/07/2009 14:17:07
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I share your frustration Timbo, my  H9 P-40 was a great disappointment
Ultymate24/07/2009 14:28:43
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Tim as Danny has already alluded to tread carefully with wing incidences on a bipe as it can turn the aeroplane into a right "dog" if you get them wrong. I would have thought only the top wing could vary incidence wise, although if all the components are CNC produced there should be no error there either.
                        The Sopwith Camel has always been a notorious model to balance however powered and whatever scale it's built to at least you've got some useful ballast up front in the form of batteries and not the usual church ( or for us in WalesChapel) roof under the cowl. Don't resort to arsen just yet I'm sure all will be resolved
 Cheers Brian

Edited By Ultymate on 24/07/2009 14:29:44

Danny Fenton24/07/2009 15:13:56
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Now you guys have made me very wary of hangar 9, I thought that they were supposed to be very good, but it sounds as though they are just the same as the rest........
 
Its times like this when you want a talking head from Hangar 9 available to comment. And it makes you realise how good some suppliers are that join in on forums. ( I am imediately thinking of John Emms @ Puffin , and Eddie Stocker of DB Sport and Scale.) sorry if I have missed off others......
 
It is an unfortunate fact of life that these days it is cheaper to manage customer dissatisfaction than achieve customer sattisfaction.
 
I have every confidence that Timbo will crack it, at worst it will end up a low wing monoplane dromedary

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