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Another 'HOTS' only bigger !

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Old 04-14-2010, 07:51 PM
  #51
john josey
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Default RE: Another 'HOTS' only bigger !

I use what is effectively 'wig' tape to hold the various parts to the bench for sanding or shaping, as i find it holds very well and rubs off very easily with no damage. i also use it to stick the blanks for the formers together before being trimmed to their final shape on the disc sander.

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Old 04-14-2010, 07:56 PM
  #52
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Default RE: Another 'HOTS' only bigger !


Quote:
ORIGINAL: davidgeorge212

ive been following your progress, You do some really good looking work.

David
Hi David,

Thanks for the kind words, i appreciate it.

I havent managed as much time as i would have liked on it but we`ll get there.

cheers
john
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Old 04-15-2010, 04:16 PM
  #53
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Default RE: Another 'HOTS' only bigger !

Managed another couple of hours today. Chamfered the leading edges of the rudder and elevators and rounded off the leading edges on both the tailplane and fin.


Final sanding before fitting to the fusalage.
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Old 04-15-2010, 04:27 PM
  #54
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Default RE: Another 'HOTS' only bigger !

I added some balsa to brace the fusalage sides while i add the tail and top/side sheeting, to keep things square.

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Old 04-15-2010, 08:00 PM
  #55
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Default RE: Another 'HOTS' only bigger !

Tail finally aligned and glued in place. It`s starting to come together now.

Just really the wing tips and fusalage sheeting to do before the covering starts, although i will be adding a cowl made from 1/2 sheet.



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Old 04-16-2010, 03:37 PM
  #56
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Default RE: Another 'HOTS' only bigger !

Shaped the rear spine from 1/2 " sheet.


Sheeting cut and shaped ready to be glued on.
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Old 04-20-2010, 07:07 PM
  #57
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Default RE: Another 'HOTS' only bigger !

Back to my techie drawing days at school with scaling up the wingtip from the smaller one. I`m so glad i choose to increase it by 50% as it`s so easy to calculate.



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Old 04-20-2010, 07:18 PM
  #58
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Default RE: Another 'HOTS' only bigger !

Forgot about this one, sheeting glued and sanded to fusalage rear.

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Old 04-20-2010, 07:33 PM
  #59
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Default RE: Another 'HOTS' only bigger !


Thats the easy bit done !

I know a lot of guys just go for a flat tip, but for me the hots has to have the curved tips.
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Old 04-20-2010, 07:48 PM
  #60
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Default RE: Another 'HOTS' only bigger !

It took me a while to get the shape of the first piece of sheeting with all the trial fitting and trimming, but the other three only took a short time as i just had to draw round them.



And the hard part done (thank goodnees)
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Old 04-21-2010, 04:00 PM
  #61
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Default RE: Another 'HOTS' only bigger !

Finished off the sheeting on the wingtips. All thats left on the wings is to hinge the ailerons and final sand before covering.

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Old 04-21-2010, 06:46 PM
  #62
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Default RE: Another 'HOTS' only bigger !

I decided to make individule servo mounts instead of the usuall 'rails' because the throttle linkage will be near the bottom of the fusalage and will require a mounting position very different to the rudder and elevator servos.

I have taken pictures of the various steps in making them if it`s of any interest. Started off with a sheet of 3mm birch ply and 8mm square hardwood for the bearers.


Individule parts cut roughly to shape but over size


When cutting the bearers to the rough lenth, you need to have a perfectly square end at one end so that when you glue them to the base plate they sit square off it. This can take a bit of time as you need to go back and forth between the sander and bandsaw.


The first job is to glue the bearers to the base plate with the correct spacing for the servo being used. i used a piece of scrap ply cut at 1mm bigger than the width of the servo, in this case 41mm.


The only thing you have to do on these end pieces is have one good flat edge to glue to the base plate, and make sure they stick out by the bearers 0.5mm or so.




This next picture shows the first face to be finished off on the sander, where the servo screws on to.


All trimmed down on the sander to the finished size.


I just attached them with double sided tape roughly in place to give an idea why i decided not to go with the conventional rails.
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Old 04-22-2010, 04:26 PM
  #63
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Default RE: Another 'HOTS' only bigger !

Added the undercarrige plate today. I decided to add a smaller piece at the angle on the bottom of the fusalage, to give the bottom sheeting something substantial to fix to at that point.




All glued in place.
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Old 04-22-2010, 04:51 PM
  #64
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Default RE: Another 'HOTS' only bigger !

This is the first look i`ve had of the engine to be used, an OS 91 FX and by the look of it, it`s only had a few tanks through it, not a mark on the internals.


Drilled the holes on the bulkhead for the engine mount. The mount rotated to have the tuned pipe running down the centre of the fusalage and the height to suit the 70mm spinner lining up with the top of the fusalage.


The last jobs i managed to get done were the top sheeting between the bulkhead and former 1, the 3mm plywood 'ring' and the 1.5mm spacer to the back of the spinner.


Hopefully get the cowl done tomorrow.
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Old 04-22-2010, 04:55 PM
  #65
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Default RE: Another 'HOTS' only bigger !

Hi John. I started construction of my 160% Hots too a few days ago.
By now I´m about 3 days into the build, and the top side of the wing is almost ready to be sheeted. After that I will turn it over and sheet the other side.

The front part of the fuselage has a plywood "box" which contains the engine and wing mount. It´s made from 3mm plywood side doublers and bulkheads, but with a 5mm ply firewall. The 5mm fuselage sides are glued to this box and joined in the end.
I dont have pictures from todays work, but I´m a little bit more ahead than the pictures show.

Unfortunately my phone is primarily for calling people, so the internal 2 MP cam sucks a bit...:-)

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Old 04-22-2010, 05:01 PM
  #66
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Default RE: Another 'HOTS' only bigger !

The undercarrage arrived today so i just taped it on to see how it would look.

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Old 04-22-2010, 06:35 PM
  #67
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Default RE: Another 'HOTS' only bigger !

Hi Tinus,

Thanks for posting the pictures. I`m really interested to see how it was intended to be constructed compared to what i have done. I can see what you mean with the 'box' on the inside of the fusalage sides, but the wings seem to be very different to what i have.

Keep up the good work and please feel free to post as many pictures as you want. It would be good to see your build along side this one for comparison.

I too have the same problem with taking pictures, i can only do it from my phone.
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Old 04-22-2010, 07:04 PM
  #68
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Default RE: Another 'HOTS' only bigger !

The wing is more or less standard aside from the 5x10mm subspars I´m installing to the rear of the wing. These also doubles as part of the wing servo mounting. The main diference is in the mounting of the wing. Since I´m installing a 500ml fuel tank I didn´t have room to put the dowels in the leading edge of the wing which would be the normal procedure, so they are located higher up in the bulkhead above the wing.

I used 3mm liteply webbing on the 10x10mm main spars and I will be fully sheeting the wing with 2mm balsa.
This will make it a bit heavier than a stock built Hots, but since I´m also installing an engine quite a bit larger I like it to be a bit more solid.

I´m hoping of a finished weight of around 6 kg which should be OK for the available power.
I´m using an APC 18x10 on the engine, and at the moment it´s spinning this at around 7600-7800rpm, but I have a new carb coming which may boost this number a bit since the carb I´m using now is smaller, and seems to be suffering from a blocked high-speed circuit.

I will take some more pictures tomorrow showing the progress.
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Old 04-22-2010, 07:15 PM
  #69
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Default RE: Another 'HOTS' only bigger !

Will you have space to fit a cowl with the bigger engine ? Sheeting the wing with the bigger model is a good idea, i just hate sanding the joins.
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Old 04-22-2010, 11:49 PM
  #70
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Default RE: Another 'HOTS' only bigger !

John,

I've been following your build with interest. Always nice to see scratch or scaled up/down projects.

One comment regarding your 91 FX: they are widely rumored to cause the fuel to develop bubbles due to vibration at the needle valve assembly on the backplate. There was a revision of the engine by OS and the later ones were made with a standard backplate with a bolt on assembly for the needle valve. From factory it came assembled on to the backplate but was easily removed and attached to some other location on the airframe. This solved overheating and dead stick situations which were being widely reported. If you take a look at the current engine on Tower you'll see how the engine looks now.

Your engine appears to be of early vintage with the backplate and needle valve as part of the same assembly. It might be worth checking into a replacement backplate and needle valve so that you can locate the latter somewhere else on the model. I believe that a simple ply plate on the side of the cowl would be a fine location. It's just a matter of getting it off the engine case.

You might find this thread of interest:

http://www.rcgroups.com/forums/showthread.php?t=147756

I have one too but I bought it from a friend and have yet to pick it up (a year later...). When I do later this summer, I'll probably do the same on mine if its of the older vintage.

Keep up the great work and thanks for your thread.

David.

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Old 04-23-2010, 12:06 AM
  #71
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Default RE: Another 'HOTS' only bigger !

John,

this 60 size Hots with a 91 FX shows the new needle valve assembly:

http://www.theflyingknights.com/phpB...3b57e&start=15

David.
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Old 04-23-2010, 05:23 AM
  #72
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Default RE: Another 'HOTS' only bigger !

@ John: I plan on sheeting the wing in one go with an already assembled and sanded sheet, but I have yet to decide my plan of attack.
This is the first buildup wing I have made since 1990 when I built my first model. Ever since that time I have been making foam wings which are, to me, both much easier and quicker to build. I actually wish I had done that here too.

At first I planned on making a fiberglass cowl using the "lost foam" technique, but I think I will try making a fixed wood cowl first. I should be able to mount the engine bolts through the hole in the plywood nosering when the spinner is removed. But as you say, there is not a lot of room so I may have to revise that plan...:-)
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Old 04-23-2010, 12:44 PM
  #73
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Default RE: Another 'HOTS' only bigger !

Very nice builds going here. I just started a Super Hots 60 from the Santich plans the other day. Doing the wing now and it is very easy and straightforward! I would like to see more on building up the wood cowl-I am building from plans alone....no instructions whatsoever so I am not 100% sure how to proceed with the cowling.

Thanks!
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Old 04-23-2010, 04:57 PM
  #74
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Default RE: Another 'HOTS' only bigger !

What airfoil is the hots wing built around?
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Old 04-23-2010, 06:17 PM
  #75
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Default RE: Another 'HOTS' only bigger !

Don´t think it´s an official "named" airfoil since the ailerons are stuck-on the TE giving the airfoil a distinct S-sweep.
I´m at work now and I have only MS Paint available, but I have tried to draw the basic layout of the airfoil.
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