Burnhard
Well-known member
Can‘t have enough spinners. Got excited.
Building the FT Mosquito Master Series 50“
- Thread starter Burnhard
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Burnhard
Well-known member
Work on the Mosquito has started. The weeks has been crazy and so far I have just glued together the various formers.
The set includes nine sheets of fomeboard and seems more massive than the C47 of the same size. The powerpods are much bigger than the ones on the C47 50“ version.
Also my list of mods is growing.
This should certainly keep me busy for the next month or so.
The set includes nine sheets of fomeboard and seems more massive than the C47 of the same size. The powerpods are much bigger than the ones on the C47 50“ version.
Also my list of mods is growing.
- Will definitely try to include the retracts. The nacelles seem to be pretty large so it should be possible to add some decent size wheels.
- Would like to add a stearable tail wheel. The tricky part will be that I think it cannot be hooked directly to the rudder but will need to have an own connection to the servo for the rudder.
- Speaking about the rudder, I would like this to be operational as well. It appears that the rudder is supposed to only be glued to the top of the back part of the fuselage. Will strengthen that with a bbq skewer.
- Also want to do flaps. Will need to come up with a solution to move both flaps on one side of the wing with one servo.
- And last but not least, the large bottom plate shown in the special features video sort of demands to try to add doors for a bomb bay. I guess the tricky part will be to come up with something that allows the foam to stay in form once it has the bent shape.
This should certainly keep me busy for the next month or so.
Burnhard
Well-known member
Did some initial scouting for the retracts. There seem to be two potential options where to put it: either directly before the half former (looking from the back of the nacelle) or after that former. As with everything in life, both have their advantages and disadvantages.
Putting it in front of the former has the benefit of not having to cut the former and generally seems to be the easier fit. That way it seems to fit right in front of the front wing spar which seems to run directly over the former. There is also an opening in the wing there.
Putting it behind that former would however be the more scale option as the original landing gear seems to sit very much on the leading edge. However, this seems to be much more fiddling.
I think I will build another nacelle as a test dummy. That way I can also figure out whether it is worth to try to create moving doors for the landing gear.
Putting it in front of the former has the benefit of not having to cut the former and generally seems to be the easier fit. That way it seems to fit right in front of the front wing spar which seems to run directly over the former. There is also an opening in the wing there.
Putting it behind that former would however be the more scale option as the original landing gear seems to sit very much on the leading edge. However, this seems to be much more fiddling.
I think I will build another nacelle as a test dummy. That way I can also figure out whether it is worth to try to create moving doors for the landing gear.
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Burnhard
Well-known member
Had some busy weeks with only little time to work on the Mosquito. I finished the stearable backwheel. It fits quite nicely.
Next thing will be some test fitting for the rudder. Then I will know where to cut the hole for the tube. And once I do have that, I can happily continue on the fuselage.
As fir the retracts, I created a copy of the right nacelle and the lower part of the wing. As a starter I tried to position the retract behind the half former and the wheel behind the spar towards the leading edge. I am not too sure whether I like that so I will try to move the retract before the half former and the wheel in the cut out of the wing. Will post pictures when im there.
Next thing will be some test fitting for the rudder. Then I will know where to cut the hole for the tube. And once I do have that, I can happily continue on the fuselage.
As fir the retracts, I created a copy of the right nacelle and the lower part of the wing. As a starter I tried to position the retract behind the half former and the wheel behind the spar towards the leading edge. I am not too sure whether I like that so I will try to move the retract before the half former and the wheel in the cut out of the wing. Will post pictures when im there.
Opus
Member
Just finished my Mossie. Not exactly museum quality but I think it will fly. Waiting for the snow to melt.
Mods: I made a clear canopy in anticipation of FPV. Added radiators on the leading edge which are functional as that is where the ESCs reside. Retracts are from an old Mosquito. Added steerable tail wheel and rudder.
If I were to do it over I would get some dense foam and carve items like the nose. Trying to shape foam board into compound curves is difficult and can never look as good as hand shaped foam or balsa blocks.
Mods: I made a clear canopy in anticipation of FPV. Added radiators on the leading edge which are functional as that is where the ESCs reside. Retracts are from an old Mosquito. Added steerable tail wheel and rudder.
If I were to do it over I would get some dense foam and carve items like the nose. Trying to shape foam board into compound curves is difficult and can never look as good as hand shaped foam or balsa blocks.
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Burnhard
Well-known member
Yours looks really great! Just a few questions on how you did the landing gear. Looking at the picture you placed the gear before the former, correct? Do the doors close and if yes, how did you make that?
Opus
Member
I made a small plywood reinforcement that I glued to the underside of that "U" shaped foam piece behind the motor. The gear is screwed to that. Gear legs are directly below the leading edge of the wing. This is an old-style retract with the servo at the back of the nacelle. You can see the push/pull rod in the photo. Barely visible is a short piece of fishing line connected to the upper part of the doors. The retracting gear engages this line and pulls the doors shut. This involves a little trial-and-error on the length and position of the fishing line. The servos are connected to different channels on the Taranis receiver so that I could adjust their throw.
One of the most beautiful airplanes ever made . .
One of the most beautiful airplanes ever made . .
Burnhard
Well-known member
Thats very helpful! Nicely done. The landing gear looks pretty scale with the two legs.
I will need to use larger wheels as I am starting from and landing on a grass field. Still trying to figure out how to do a two leg landing gear as DIY.
Opus
Member
Still trying to figure out how to do a two leg landing gear as DIY.[/QUOTE]
Idea -
If you are using servo-less retracts: The moving part on this type of retract system has setscrews that screw in to secure the gear leg. Remove the setscrews and add two machine screws and you now have a way to attach two gear legs.
Idea -
Burnhard
Well-known member
Idea - View attachment 222819 If you are using servo-less retracts: The moving part on this type of retract system has setscrews that screw in to secure the gear leg. Remove the setscrews and add two machine screws and you now have a way to attach two gear legs.[/QUOTE]
Thats exactly the retracts I am going to use. I am more struggling to come up with an idea on how to do the two legs and how to join these up, so that they fit into the hole of the retracts.
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Opus
Member
Thats exactly the retracts I am going to use. I am more struggling to come up with an idea on how to do the two legs and how to join these up, so that they fit into the hole of the retracts.[/QUOTE]
My idea was to use two machine screws through the top of the gear legs into the threaded holes that had the set screws. You then mount the retract assembly inverted. You would also need to connect the legs with a cross piece and probably key and notch the moving piece. Or maybe one long machine screw all the way through with a nut on the end. If I were doing it I would make a new moving piece with longer axles that I could firmly attach the gear legs to.
Re-thinking this: I don't know what skills or tools you have so my idea may not be practical. I hope hat you figure out a way to build your landing gear the way that you want it.
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Burnhard
Well-known member
Over the last weeks I finished the fuselage and the nacelles and I also prepared the vertical and horizontal stabilizer, canopy and lower wing skins.
On the landing gear I did a test fit with the dummy nacelle I created. I started with fitting the retracts after the former. That generally seems to work but there are a few things that I am not too happy about. First, with that setup the wheel sits pretty far back in the nacelle which means that the door needs to go pretty long way back. Also, when the retract is in landing mode, the wheel has only little space over the nacelle. I have therefore decided to move the retract further to the leading edge (like @Opus did for his one) before the former. It appears that my wheels are a bit too large (I was planning to use some 75mm wheels) so I will rather try something around 60-65 mm. For the leg for now I will use a single leg but will prepare the inner workings of the nacelle so that I can use a double leg later if I find a suitable solution.
Also made up my mind on the order how I will put things together. Once I am happy with the retracts in the nacelle, I will fix the nacelle to the lower wing skin. Then I plan to add a bit of carbon fibre to strengthen the wing. Next step will then be preparing the double flaps before closing the wing with the upper wing skins.
On the flaps I am thinking to make these move with one servo only which sits flush with the lower wing skin in the back of the nacelle and with the servo arm pointing inside the wing skin. That servo than links to a pushrod which connects to a carbon tube connecting both flaps. Will need to test that as well before putting pieces together.
On the landing gear I did a test fit with the dummy nacelle I created. I started with fitting the retracts after the former. That generally seems to work but there are a few things that I am not too happy about. First, with that setup the wheel sits pretty far back in the nacelle which means that the door needs to go pretty long way back. Also, when the retract is in landing mode, the wheel has only little space over the nacelle. I have therefore decided to move the retract further to the leading edge (like @Opus did for his one) before the former. It appears that my wheels are a bit too large (I was planning to use some 75mm wheels) so I will rather try something around 60-65 mm. For the leg for now I will use a single leg but will prepare the inner workings of the nacelle so that I can use a double leg later if I find a suitable solution.
Also made up my mind on the order how I will put things together. Once I am happy with the retracts in the nacelle, I will fix the nacelle to the lower wing skin. Then I plan to add a bit of carbon fibre to strengthen the wing. Next step will then be preparing the double flaps before closing the wing with the upper wing skins.
On the flaps I am thinking to make these move with one servo only which sits flush with the lower wing skin in the back of the nacelle and with the servo arm pointing inside the wing skin. That servo than links to a pushrod which connects to a carbon tube connecting both flaps. Will need to test that as well before putting pieces together.
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Opus
Member
Looking good. And flaps too? Ambitious. The Fliteline Seafury has split flaps. One servo on each side with two pushrods off of each servo to the flaps. Works good.
Burnhard
Well-known member
I like the occasional challenge ;-). Just had a look at the seafury. Like the Idea with the two pushrods. Less complex than my T-connection. Still plan to put the pushrods inside the wing. Did that with my P51 as well.
Opus
Member
Food for thought: Of all the moving surfaces on an airplane, the flaps carry the biggest load. The servos that drop the flaps are under continuous strain as long as they are down. I have seen flap servos fail in flight because the pilot had flaps down and then was adding power and diving the plane. One side failed, creating an assymetrical situation instantly and a nasty UN-commanded roll. So, however you engineer your flaps, give the servos as much mechanical leverage as you can.
Burnhard
Well-known member
This is actually a good piece of advice. You basically have two options, either a pull or a push configuration. Most models that I am aware of use a pull configuration where the control horn is pulled towards the servo. In my P51 (and also my Spitfire) I have used a push configuration where the control horn is pushed away from the servo. The benefit of the pull configuration is that it seems to imply less stress on the servo. The benefit of the push configuration is, that you can hide all pushrods and control horns in the wing. I am planning to use some Emax digital servos with a metal gear. Will check on the specifications to see how much margin I have with these.
Burnhard
Well-known member
Double checked my servos. I will be using one Emax ES08MD II for the flaps on each side. These can carry a load of 1.6 to 2 KG. Hope that leaves enough margin.
Burnhard
Well-known member
Did a second test fitting of the retracts on my test setting yesterday. Moved the retracts to the leading edge of the lower wing skin. Also used slightly smaller wheels with only 65 mm diameter. This looks and works much better. Also tried the closing mechanism for the doors with the fishing line as @Opus suggested. Worked perfectly. Will need to come up with a mechanism for keeping the doors open. Maybe a spring from a pen. Will start working on the real thing tonight.
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