john josey

I managed to build a 48" hots from an old crashed airframe at the end of last year, so a friend of mine has asked if i could build him a bigger one.

After a short chat we decided to increase it by 50% which will take it to around 72" (maybe a bit bigger when you add the wingtips)

I started off by cutting the scaled up size from thin card.


When i built the small one i made a kit of parts for two, so all i`m doing here is scaling up from the second kit of parts of the small one, if that makes sense ?

john josey

Used the card templates to mark out the front bulkhead and undercarriage plate. These are the only parts that are cut from 6mm birch ply, the others are from 3mm light ply.

I was extra carefull with the front bulkhead being square as this is used as a template for the width of the rest of the formers including the undercarrige plate.

Formers 2 and 3 roughly cut to shape using the card templates.

john josey

Decided to make a start on the wings simply because they are gonna take up the whole bench and the sooner their done the better !

Started by making the ribs. Made one 'master' rib from 3mm ply and used the disc sander to get them to their final shape using the ply rib as a template.

john josey

The two inboard ribs on each side have the spar cut-outs twice the depth as the spars are doubled up in the centre saction.

john josey

Obviously because of what i`m doing here there is no plan to work from, so a full lenth straight pencil line on the bench will have to do.

Fortunately the wing is symmetrical in section, parallel cord with no dihedriel, so is quite straight forward.

john josey

I use panel pins in-between every second rib, the difference being that i cut the heads off with 'side cutters' and hammer them flush with the spars. This means you can finnish the whole top of the wing including spar webbing, front, rear and centre sheeting and even the cap strips. once completed you simply 'prize' the whole wing off the board. The wing is fairly stiff at this point and much reduses the chance of being warped.

Just one word of caution with this method is dont run your hands over the board to see if you have got all the pins out  (cause that really will sting a bit !)

john josey

This is a square on shot of the centre section spars.

john josey

The leading edge was made from a single sheet of 1/2" x 36" balsa cut in half along it`s lenth.

The trailing edge was just 1/2 x 1/2 balsa joined together in the centre with a piece of hardwood and held at the correct height (22mm) with scrap balsa blocks tack glued to the bench.

The spar webbing was also added from hard 3/32 balsa sheet. You can see in this picture where the centre ribs are cut deeper for the spars and where the spar doublers end.

Unlike the small one, this wing will have to be removable so i added three 1/2 sheet balsa pieces between the two centre ribs to help spread the load of the ply plate for the wing bolt (s) when the sheeting is on. I also added a piece of 3mm birch ply between the centre ribs, mainly for a better fixing for the dowels, but also as a brace on the LE join.

john josey

Front, rear, centre section sheeting and cap strips added. Tomorrow i can prize it off the bench and complete the sheeting.

john josey

Thats the bottom sheeting and cap strips all complete. The next thing i wanted to do was the aileron servo mounts and this has turned out to take just as much time as the wing it`s self.

john josey

The basic frame to mount the aileron servo.

john josey

'Framed' out the 2mm balsa sheet with 3mm sq just to give the sheeting something to sit on. I could have sat the sheeting on the 2mm frame and just sat the ply servo mount on the hardwood blocks, but i thought this was the better way as it helps to keep the curve of the wing.


Another way would have been to use 5 or 6mm sheet.

john josey

All sheeted and cut out for the mount.




The other side should be quicker to do.

john josey

Obviously i dont build this quick  but thats it up to date now and should be normal speed.

                                                                john

john josey

Only managed a couple of hours today but managed to cut out the fusalage sides. Thats the sides of the '40' size one beside them.

SKYHI1

Very cool. Thank you for sharing.

Frank

Pelle Gris

Hi John.

I´m also about to start building a Hots scaled up by 60%. Well, as soon as I get the parts from a friend that has promised to lasercut them for me...:-)
A 60% enlargement would mean a span of 76,8in, but I have decided to dump the curved wingtips and clip the wing at 70,9in instead. Power will be an old 35cc Webra Bully running gas.

What do you plan on using for power, and what do you estimate the final weight to be?

john josey

Hi Frank,

Thanks for the kind words. I know how much i enjoy the various build threads on here and i`m always facinated be the way different modelers do different aspects of the build.

This is a very simple straightforward aeroplane to build. I realised from another thread on here that the 'HOTS' has a strong following so it may be of interest to some.

cheers
john

Pelle Gris

Pics of my modified plans and planned paint skeme in pose #2 here: http://www.rcuniverse.com/forum/m_92...tm.htm#9243384

john josey

For power my plan is to use a 'piped' OS91, as for the all up weight, i`m not sure, if it comes in at around the 12lb mark i`ll be very happy. All i can say at the moment is that the wing is very, very light at the moment.

john josey

Hi Tinus,

Thanks for posting the link, very interesting indeed.

What width is the front bulkhead when scaled up to 60% if your planning to use the big petrol engine ?

cheers
john

Pelle Gris

The maximum width of the front bulkhead is 110mm at the bottom which doesn´t leave much room for the engine, but it looks like it will fit... just. :-)
I was planning on using a tuned pipe too but a friend had a spare DA 50 canister which should work out nicely, and be quite a bit cheaper than buying a pipe.

Pelle Gris

Granted, it IS quite a lot of engine to cram into the cowl.

john josey

Yeah, but it should be great though

I`m pleased you`ve posted this, feel free to add pictures of your own at any time.

john

john josey

I glued formers 1 and 3 in permanently, but 2 i left untill i had the dowel and tank holes cut.