Top Flite P51 - 65" span

[Peter Jenkins]

I'm just about to start building this kit and noted that the plan shows an OS 120 FS for the four stroke option but all servos are clearly marked Futaba S148. That rather surprised me as I'd have thought the S148 might not have been man enough for a 120 four stroke powered model.

What has been the experience of others with the 65" span TF P51 as regards servos?

[Don Fry]

Sounds OK.. We over servo and over power aircraft nowadays because we can. Accept that the designer may have had basic competence.

[Robert Parker]

Hi Peter,

I have the TF P40 and that too has the S148 servos and a 120 FS motor shown on the plans. The kit design is quite old, my plans were drawn in 1993, and the 148 servo was a common choice back in the day if memory serve me right. I went for the 2 stroke option.

The kit builds fine and quickly.

Regards

Robert

[Trevor]

I'd build it as per plan then, with the control surface deflected (using either the transmitter or a servo tester), push back on the surface with your hand, stopping when the servo moves or when you feel you're about to break something.

Of course, if your builder's intuition lets you down and you do break something, at least you know the servo is okay

Trevor

[Jon H]

148's will be fine. I used them on my 72'' 155 powered P40 and had no bother.

Just dont open the throttle in a dive. 120 is well OTT for that model and you may flutter the tail off.

[Peter Jenkins]

Thanks for your input guys, much appreciated.

[Peter Jenkins]

Sorry about the long delay in progressing this build! Other things got in the way until we all came to a shuddering halt earlier this week! I also carried out a good deal of research into a number of topics during this time. So, after finishing the maintenance tasks on my two front line F3A competition mounts, I decided that now was the time to start the Mustang build.

After some consideration, I've decided to build this aircraft to depict the Mustang IV operated by 303 Squadron. As many of you will know, 303 Squadron was one of the squadrons formed from Polish aircrew during 1940 and who were only allowed into the Battle of Britain after a Polish pilot became frustrated that the RAF insisted on training flights that he broke away from the squadron during a German raid and shot down an enemy aircraft. The Poles were then allowed to become operational and 303 Squadron ended the BoB as the highest scoring RAF squadron despite only being involved from Aug 1940.

It is a tragedy that the country on whose behalf Britain entered WW2 was allowed to remain under Russian occupation for so long and that we so often hear that Britain stood alone against Germany after the fall of France. The British Empire was no weakling and there were many nationalities from within the then British Empire who participated in the BoB as well as pilots from Poland, Czechoslovakia and France.

So this is my tribute to the Polish pilots who fought so effectively for their freedom through service with the RAF.

I bought this kit as an unstarted secondhand kit. I then bought an OS120 FS also second hand, and, after further consideration, some second hand Robo struts. That led to the decision to buy some new Robart electric retracts which rather blew the original idea of buying everything second hand and the budget! I also wanted to fit a full set of doors and a retracting tailwheel. I was pointed in the direction of Hobby King and acquired an undercarriage and door sequencer. I don't know if the sequencer was designed around the Robart electric retracts but the timing of gear and door operation is just perfect.

Every journey begins with the first step, so today I opened the box with the intention of not closing the lid until I had finished. To kick off, here's the open box with the plan, manual and graphics sheets removed so you can see that I really am starting with a box full of balsa, ply and a couple of fibreglass mouldings!

The manual starts with the construction of the tailplane. But, trying to find the relevant parts was no easy matter. So, bit the bullet, and decided to pop out all the die cut parts into 3 groups: fuselage, wing and tail unit. The die cutting is very good and there were only a couple of occasions that I needed to resort to a modelling knife to persuade the part to fall out. The photo below shows an example of the die cutting.

After an hour and a half, I had sorted all the ply parts as you can see below. Tomorrow I'll set to on the 9 sheets of balsa die cut parts before I can really start the building. As I've become sensitised to CA glue, I'll be using aliphatic glue so progress will not be quite as fast as if I were to use CA glue.

The ice cream containers have been lying around the workshop waiting for something useful to do.  They are great for holding the smaller die cut parts!

Edited By Peter Jenkins on 27/03/2020 23:53:39

[Ron Gray]

Good to see you turning your attention to non F3A things Peter!

[Peter Jenkins]

Only till the lockdown ends Ron 😉

[Ron Gray]

In that case, how many more kits have you got??

[Peter Jenkins]

2. One's a Taurus - 1960 revolution in aerobatic design - and another TF P51! The Taurus will be next up. But, I've got to get through this one first!

[DaveyP]

Hi Peter, glad to see you have now started, I will follow your progress with interest

All the best, Davey

[Tim Flyer]

I’m watching this one with interest too. It sounds like it will be fun with the 120. I have a spare Laser 80 and an OS 95 v kicking around too although my garage ceiling is a bit full with 10 IC planes in ready to fly condition . I’m almost missing not having a build going now . Anyway I look forward to seeing this one take shape😊

[Peter Jenkins]

This morning I spent almost an hour and a half identifying, marking and punching out all the balsa die cut parts!

The first session after lunch was finding and setting up all the components of the first item to build according to the manual, the tailplane. Here are all the bits assembled and ready for glueing.

The next session was setting up and glueing the bits together. I have started off with firm intentions of building everything square and so my trusty mini try square was pressed into use.

This was rather protracted as I kept breaking off the tabs on the bottom of the ribs! The ribs were quite hard balsa but the tabs still snapped very easily! It's called a learning curve! After a couple of false starts, I finally got the starboard side glued up and the port side proved a good deal easier! As I'm using aliphatic glue, I've not left the stabiliser, as they call it, pinned down to dry off overnight as the next stage requires the use of a razor plane and sanding block! So, this is what it looks like now.

More tomorrow if the grim reaper spares me!

[Peter Jenkins]

No building today, but a lot of thinking. I want to replicate the Mustang control hingeing as opposed to the usual V gap and mylar hinge. TF do hinge the flap in the correct way so I am looking at drawing up the same type of hingeing for the ailerons, elevators and rudder. I will need to see if there is a supply of Robart type hinge point hinges that are smaller than the ones I have (309). Having consulted the Robart site it looks like I'll need their 306 size (3/32 in) so I've just sent off for some.

Using the scale function, the front of the control surface is shrouded by the trailing edge of the wing/elevator/rudder, so the sheeting that covers the surface needs to be extended aft and then sanded to accommodate the rounded end of the control surface.

I will also be building in the counterbalance tabs in the elevator and rudder since they are quite a prominent sight on the aircraft. This requires some additional structure in the tail plane and fin to allow the structure to be cut away for the balance tab. While I'm not aiming for a highly scale aircraft, I think these changes will make a big difference to the way the aircraft looks to anyone familiar with the sleek lines of the full size. That's also why I'm going to put up with the pain of installing a retracting tail wheel and the full complement of u/c doors that include the inboard ones that open and shut to allow main gear extension. I'm sure I'll come to regret this as I build the beast!

Incidentally, the tail plane structure is now dry, and remarkably solid, but on removing it from the building board the outboard starboard rib became unglued! So a dob of aliphatic and it can dry overnight ready for an assault with the Permagrit sanding block to tidy up the end face ready for the tip block in due course.

[Peter Jenkins]

After a slight delay, I have done a bit more on the tail plane. I now have some Robart 3/32" hinges and the first thing I noticed was that far from being half the size of the 3/16" hinges they are about 1/4 the size. I think that if I used 4 per side that will provide adequate strength for keeping the elevators attached! Incidentally, I found a new supplier for these Robart hinges who is well worth using. He trades under the name of Darbro RC Models. Darrin is incredibly helpful. The hinges arrived the day after I ordered them which is a great credit to him and to the Post Office. Incidentally, it is cheaper to go to him directly rather than buying via E-bay.

I have also built up the tail plane trailing edge structure with some 1/16" square strips. As I was out of this size strip, I was pleased that I had kept hold of the die cut sheets as I used one to cut out the strips. Must get a balsa stripper if I'm going to continue building! I will cut he 1/16" sheeting so that it extends by 1/8" behind the end of the tail plane rear spar. My aim will be to cut the double tapered elevators to size, sand the LE to a nice round shape and then wrap some sand paper around the nose and use that to sand a concave circular profile in the trailing edge structure as in the photo below.

The other task I've carried out is to put in place the structure to allow some of the tail plane structure to be cut away to allow space for the elevator balance tab.

[Darrin Pretorius 1]

I noticed your mention of the size difference between the 3/32 and the 3/16 Robart hinges. I wonder if the 1/8 might not have been a little better?

[Martian]

Another lovely build to follow the Mustang is a super looking plane

[Chris Freeman 3]

Very nice project. My advise would be to not complicate things too much and try and keep the weight off as the wood in this kit is quite heavy. I scratch built one and covered in film and made it electric and love the way it flies. Used standard Futaba 3001 servos on all control surfaces.

[Tim Flyer]

Nice Model Chris👍

[Peter Jenkins]

Posted by Darrin Pretorius 1 on 01/04/2020 11:40:47:

I noticed your mention of the size difference between the 3/32 and the 3/16 Robart hinges. I wonder if the 1/8 might not have been a little better?

You make a good point Darrin. Do you have any in stock? I'll PM you my email address.

Peter

[Peter Jenkins]

Hi Chris

Nice looking model. Hope mine comes out as good as that. Thanks for the warning not to over complicate things but I will take care not to add too much weight. I know that the fuselage structure looks pretty solid and I wonder if there might not be some opportunity to save weight there. However, with an OS 120 FS up front I suspect that model could do with a little extra weight that a retracting tail wheel will add. I don't think doors will add a lot of weight but will complicate things. The sequencer for the main door operation I already have and it works really well with the Robart electric retracts so the only issue is building and hingeing the doors. Not looking forward to that!

Are there any poo traps I should watch out for in the build? I've read the construction manual through several times to try and get a picture of the build in my brain and I cannot see any issues at the moment. That, of course, will change when I hit them!

Peter

[Peter Jenkins]

This morning, the postman brought me a book I'd seen on Mustangs flown by the Polish pilots in 303 Sqn. There are some lovely photographs of the Mustang IV or P51D model giving a host of detail that is tempting but I will pass up! Here's the front cover and as I'm sure you will agree the finish will be a lot easier than going for the camouflage that was used by the RAF up until Mar/Apr 1945. The aircraft I intend to depict was flown by the last 303 Sqn Cdr who was also one of the original group of pilots who formed 303 in Aug 1940 and flew in the B of B. He got 3 kills in the Battle and a total of 8 kills and 3 probables. He was also the last CO of 303 Sqn and was there at the end of 1946 when the squadron was disestablished at RAF Hethel. Must have been a very sad day for the Poles given that their homeland had become a no go area for them after the war.

[Peter Jenkins]

As I'm using aliphatic glue, my progress is not as blazingly fast as the manual would have you believe! What I have done today is to make up the four sets of skins to cover the tailplane top and bottom and left and right. They are drying off in the shed and I hope to get the top skins on tomorrow. The photo shows just 2 of the skins together with a drill jig I made up from some scrap ply (resting on the pliers) in order to drill the hinge point hole in the centre of the tail plane and elevator. Given Darrin's input, I'm probably going to move up to the 1/8" Robart hinges.

[DaveyP]

Hi Peter, steady progress and I do like your drill jig idea

Dave P