Spitfire rework

[Bobby]

Well I'm back 1yr ago July 2019 Angela (Wife) fell from side bank compound fracture of wrist, just prior I had been bitten by some pesky insect on the wrist after a major reaction my Dr. thought Lymes 2nd Dr. thought reactive Eczema after skin punch test / blood test showed all were incorrect, sent to Top sausage for new appointment guess what cancelled Covid 19, how have I made 84 yrs, I put it down to a double whisky every night. So onwards and upwards, after my Pup with a 90fs was a success made me think about the Spit up in the loft with it's stupid oversize T/P and non scale like U/C. I have done a guesstimate of a nearer scale (see pic ) T/P.

[Bobby]

Having removed the T/P assembly and using Tony Ni's 70" Spit plan for a scale type T/P, I needed to reduce his by 7% to be the correct size for mine, made a template to the -7% size and then drew round it on the remaining film of the T/P and it does seem small !!??. My model is a Sportsman Aviation 65" span with the correct scale dihedral on assembly way back when ! she was so easy to fly and land a newbie could do it . The original T/P is just a bit bigger than Tony's which would explain it ? so what to do a 5% reduction or then again how accurate is Tony's. Must think before I cut !!

[alan p]

If it flew ok apart from the aesthetics, why possibly muck up its benign flying manners by altering it. But can understand knowing some thing is not quite right can be a irritant.

[Bobby]

Alan p thank you for your input and I do get your point, but as you say just looking at it can and does in this case become an irritant, while those around you have more scale looks it makes you realize how bad your one appears cartoon like. As for changing the U/C retracts that does look some what difficult, as I intend to spend no more money on it ( maybe some film for the back end ) ?. I am now on a further no fly time, only managing 3 trips this year so far, I also need something to do. Dam Covid 19. Bob

[Engine Doctor]

Hi Bobby good luck with your Spitfire re-work., an interesting post. The U/C should be a easy workable mod as they were fitted that way to make ground handling easier . The TP re-work will definitely look better but beware , a scale TP can have a BIG difference on flying characteristics especially at low speeds. .

[David Holland 2]

Just a thought but, bearing in mind that most warbirds are quite pitch sensitive, could you reduce the area of the elevators and a bit of judicious reshaping of the tips of the fixed tailplane to give you the result you're looking for? I grant you that from the picture above the tail area is well porky and if you reduced the elevator area to about where you've marked and blend into the tailplane tips that might do the job.

David

[Bobby]

Engine Doctor Thank you for your interest and I do like your information re flight characteristic changes .I do think now, how much do I want a scale-ish against cartoon, this is food for thought (-5% as against -7%) David 2 thank you also for your suggestion, but as the T/P is already removed I think I will remain on current course it could have been a compromise had I thought early on the path to this, your suggestion! U/C yet to look into a lot of work maybe ?                 Bob 

Edited By Bobby on 25/09/2020 15:50:31

[Bobby]

This is my progress to date T/P and Elevators require to be sanded to final shape. Having opened my balsa box for a Sht of 5/16" it came to me having made a L/E template and to save cutting a new Sht, what about David 2 suggestion low and behold with the bits I had cut off, I could make gussets and modify old L/E to be almost the same as the template Jobs a good one as the saying goes

[MattyB]

Interesting project... If you want you can enter it in our Dark nights fix-up challenge, we are at ~32 airframes and counting...

[Bobby]

Hi MattyB Just came back to update, sorry no chance of my being able to complete within the time frame for your thread, Man oh man my reworking Ultimate thread started Dec 18 then life for Anglea (wife) and I took its toll, the Ultimate was ready to fly July 20 then Covid 19 again, leading to a further delay so maybe March 21.

Spit update decided to drop scale U/C mod in favour of just reversing the original, scale type would be far too much rework ( tape on wing shows where it should go) have extended the beams by 5/16" and will dowel peg for security end on later, trying to purchase new legs as one broke on re-bending which is to be expected after heating (high carbon content) with a flame, not holding my breath of finding any? so may! God forbid make my own. Back to the fuse meanwhile.

[Bobby]

I seem to have fallen behind in posting Pics, as you will see the tail end is now complete less the covering of which I do not have any!, yet another problem of purchasing a small amount , having looked at Hobbyking 5mtrs only or other companies only selling the expensive stuff , this leaves me to just place it in the corner until ! . Purchased adjustable axle shafts for the u/c legs which will relieve me of manufacturing them hopefully!. I have the wire and the best tool for doing so, but I just do not want the bother! .

[Gary Clark 1]

Good work Bobby. It will be significantly better once you've finished and will look better in the air. It's the little details that make a big difference.

Gary

[Andy Gates]

Sorry for the slightly impertinent question but what are you meaning when you are talking about your % adjustments?

When I look at the 6th & 7th images in this tread, I do not see markings indicating 6 or 7%. Can I assume you are meaning linear measurements - if so then the reduction you are making is much greater.

[Caveman]

Bobby, for covering film look at Rapid RC

Rapid rc

Their 'own' covering film is the one that HobbyKing sell, but RapidRC sell it by the metre which is better than 5 metres!

GDB

[Bobby]

Making progress now on the retract u/c feature new ribs made from 1/8 birch and the other 1/8 light ply to make a single rib glued together and now fitted. The outer ribs removed with various tools to accommodate the eventual fitting of the wheel well parts, some support blocks to make and fit for u/c beam security.

Hi Gary C, I believe you are correct in your welcomed input as it reminds me of Pat and I flying our Spits in the Royal Park and trying to do so in formation, my spotter started to give me turning instruction that were for Pats model, as the park is a public place a call was made to land both models Pat landed in silence from the onlookers (public), I on the other hand got a round of applause on landing which goes to show that Pats model being very much scale and mine not so does not really matter to the majority of on lookers. Have now left the club after 17yrs so I guess there will be no more public adoration for I !.

Hi Caveman, thanks for the input you will see that I am now holding 2mtrs of each colour of Rapid r/c film On trying to order 1mtr it said No stock yet when changing to 2mtrs showed stock, sent email to ask why as it all come from a 5mtr roll according to their site info. No answer ,Purchased the 2mtrs of each and it turns out that the film is the exact same film as already fitted on the model. Result !!

Edited By Bobby on 25/10/2020 11:25:41

[Bobby]

Hi Andy G, We are all able to ask anything as long as it is polite!. You will see that the plan I am using to get my reduction size gives a Plan view of the tail plane also a side view of the fin/rudder, as the tail assembly is a flat plate type if you have a 7% reduction from a photo copier all the outline will be reduced uniformly by that amount and as I see it all linear measurements via station points will be accurate for the new reduced shape, but I am happy to be corrected if that is not so!! The Fin I decided to leave as is, but I may reduce the rudder size to match the 7% reduction as it is the same size as Tonys' 70" wing span plan. Sorry this was not on the before post but it seems you only get so many words for each post. Stay Safe Bobby

[Andy Gates]

Hi Bobby,

Reason I asked is that I fly an electric Spitfire from a magazine free plan which while it flies great at speed, when it gets down to landing speeds it is directionally unstable and runs out of elevator to flare properly.

The dimensions of my machine are...

Wingspan 43.75"

Wing chord 10.75"

Tailplane span 15.75"

Tailplane chord 5.125"

Rudder height 7.5"

Rudder / fin chord at top of fuselage including fillet 7.5"

[Bobby]

Once again I find myself getting behind updating - A great deal of tweaking on the u/c legs and grinding out more of the remaining ribs to achieve a better result not perfect but then nothing can ever be so !, the pics will show the retract wheel wells to make and fit, had to put the port u/c to stbd and vice versa to achieve a better looking u/c dangle which then meant the legs going further into the wing after reversing the leg coil fitment- more tweaking required !! but now ok I think ?. The leg mechanism required reversing and a 2.5mm bolt and nut fitted to stop the leg from dropping down due over travel of the abutment block. As I now have more film than I need - decided to remove more film from the model in the hope of a better and easier finish. Cutting out the butt plates for filling in the u/c bays reminded me of my child hood Keil Kraft kits.

[Bobby]

Like a bad penny I'm back. Decided to strip the fuselage as I have surplus film - yet more prep work required before covering - ie. checking and correcting the wing seating P/S / patterns for film etc, did not like the u/c legs so made new ones which leave the wheels closer to the wing surface resulting in less turbulence when flying and landing (I hope). The wheel wells were made from plastic cardboard and went well with just a coat of epoxy both side for good measure. This is turning out to be much more than was in my mind at the outset, be careful what I wish for moment I guess!!

[Bobby]

All prep work more or less finished so time for the covering phase. After I had flown the Spit for a while prior I came to the conclusion that the film in my view was poor, this being due to ingress by fuel at the into wind seams and the heat from the exhaust leading to bubbles/lifting of film etc., when trying to re-attach the film I found it to be very difficult and would sometimes just slit the film, iron it over with a low heat (a patch of black trim film to hide the unsightly result). I decided to investigate thoroughly before attempting to apply any film, following research and testing went for it by applying a small piece of film to the tail end, result "screw up" removed and did more research with a visit to hobby king info page also an ebay seller on how to apply this film adopting an half and half approach from the info "success" so far. Very temperature critical is my conclusion and as to adhesion ! Only time will tell. Going to shut down for a while as covering is the job I dislike most, strange though I do not feel the same when I am doing my favourite model a Bipe of whatever sort. Enjoy Christmas / Stay Healthy

[Bobby]

Before Christmas and after, I found it hard to continue with the covering as I really do not like the HK film and having many times applied the Solar polyester without problems, I do think Solar was the better film of the two. Still, we have to make do with what is available (Profilm too expensive). Did a check on re-covering my Pup with Oratex that was a shock No Way Man!. I did a trial with a small piece of HK film by applying an amount of Bekra10% directly to the glue and leaving for a few hours and then days, the glue was not affected in any way, so my experience of heat from the exhaust or other means softening the glue allowing fuel to penetrate any edge is confirmed, this suggests it is alright for Elec but not so good for IC models. I do find it strange that HK do not give any instructions on how best to apply their film, maybe they do not know themselves . I did read on a thread asking how this film weathers colour wise, attached a pic of this to show some colours not so good. Cleaned off the blkhd back to original and a good coat of epoxy also to fuse edge in the hope of better adhesion for the film

[Bobby]

Just a bit more progress, more or less finished the covering a small amount of touch up to do and then a final go over with the iron, had to make a template for pricking the film bay that was going to be covered over (hoping to avoid bubbles just a few so not to bad) and then halfway over next bay to finish wing. Think I will leave the covering for a while and concentrate on the U/C leg rebates for grub screw leg retention, fit a servo and then install complete U/C may even fit leg covers ?. I could really do with a new cowling but I will just have to see what I can do with it as the thing is full of holes etc. My fault !!. Cockpit to install after check over. I seem to be getting on better with the HK film but I find the glue does not action in the same way as Pro film temperature wise, which does make it harder (for me).

[Bobby]

?

[Bobby]

Do not know how to do this new system too old for new tricks could be my last post ?  Bobby. Stay safe all?

[Bobby]