CAP Mosquito

[John Timmis]

Hi everyone, 

I wondered if anyone would recognise this. A flying friend is having a shed clear out & as a result I have been given this rather nice looking Mosquito. The plan was first published by Complete a Pack who also provided wood parts. I remember seeing them advertised in the mags back in the 60's/ 70's.  The plan is still listed by Saric.

The designer is W Fleming, the wingspan is 63" , the original model had 2 Merco 35s & weighed 9lb 4 oz.  my calculator makes that a wing loading of 35oz/ sq'.

The model has been very well built so it looks as if I have a winter project to finish it off. It will be an electric conversion.

I wondered if anyone had memories of thes kits & can tell me how well they flew.

Cheers John

 

[Paul De Tourtoulon]

Crap, rubbish, hang it up in the garage or burn it !!!!

 

I built one, 2 x .40's it used to spin just after take-off, luckily both times into bushes and trees, then 2 x electric motors,

 56?? with 2200 3s battery's,  a bit better, it would 'flick' when trying to loop, more and less lead in the nose, bigger motors this went on for years, I finally gave it to the local flying club where it is hanging on the wall, the best place for it !

 

I did build the Brian Taylor one, that flys well,  I have a Bristol beaufighter with twin Saito .45 specials which flys like a dream,,

Pictures of plan and plane,,,

[John Timmis]

Hi Paul, thanks for the reply. It' s not the message I was hoping for but your experience is very useful.

I did think it might be a crash waiting to happen. Problems seem to be : high wing loading, pointy wingtips & no washout.

It looks as if it's a lost cause.The plan was to electrify it with  35/48 motors 4s  cells & make it into a belly lander with a drop off undercarriage.

Anyone else had experience of this model? All comments are helpful.

Cheers John

[John Minchell]

Leave the motors out, put all the radio gear and RX battery at the front to get the CG right and use it as PSS with reflexed up ailerons for the washout.  At least in a good breeze you can keep the relative airspeed up and hopefully not tip stall and spiral in on every flight.

[Eric Robson]

I built the CAP Mosquito from the plan many years ago but only used the plan as a guide. I built the fuselage from the plan but made the wing with wash out and made the spars( which are also the formers for the nacelles)   from a sandwich of 1/16" ply and balsa instead of the 1/4" ply . A lot of the block balsa was substituted for formers and sheet, I also selected the lightest balsa I could find for the tail feathers, The 1/2" sq beech engine mounts are over a foot long each and there is 4 of them They were replaced by 1/8" liteply in slots and normal engine mounts used, it was powered by 2 OS 25 fsr motors and flew well it was about 7.5 lb in weight.  You may have a chance if you can keep the weight down.

Eric r.

 

[Walts]

I think Eric has hit the nail on the head with these. Weight is critical. My father built one in the late 70's or early 80's. He is a notorious heavy builder. He made he's own full nacelles from fibre glass. They were very substantial and very heavy, in fact everything about he's build was extremely heavy. I remember he only ever tried to fly it once. It lasted a few seconds of violent tip stalling before flicking in. Many years later he gave it to me as I do love the Mossie. It was my intention to try and make it airworthy again. But feeling just how heavy this 62" twin with tapered wings was, and with not much prospect of making it much lighter, I ended up giving it back to him to keep as an ornament! lovely looking model, but unfortunately, one that comes with a pretty poor reputation attached!   

[Jon H]

My Dad has one of these new in a box. He also has the CAP Harrow which ended up very heavy and would tip stall. 

 

The key points have already been covered here. Keep it light, remove weight if possible, add washout, and make it lighter. My 63inch Hurricane is 9.5lbs but its got a big thick wing so i would want this to be probably around 8 and no more. 

 

Other factors like spinning on takeoff..eh this can be as much to do with pilot input as anything else. I am not trying to throw Paul or anyone else under the bus, but a spin on takeoff is almost always due to being too slow and too enthusiastic with the elevators. This model might need to accelerate to near warp speed to prevent this, but still, it should be avoidable. 

 

One thing i am curious about is the actual origin of you model as it has a removeable wing and the CAP version did not. The name of the designer is the same mind you, so perhaps its been modified. 

[Walts]

My guess is that it has been modified Jon. My dad's was definitely built from the Cap plan, and he's had a removable wing too. But my dad's was removable from underneath. I'm guessing that was he's own modification.

Regarding the tip stalling/spinning on take off. I am sure you are totally correct. I have my dads one and only effort at a take off on cine film somewhere (it really was that long ago!) and I seem to remember he was trying to yank it off the ground far too soon, although he's model may have actually needed more runway than the full size to get in the air safely! ?  

Edited September 2, 2021 by Walts
typo

[Jon H]

My Dad's Harrow was always a problem on takeoff as the undercarriage was much shorter than scale. This meant it sat very low, often dragging its belly in the grass and it would trip itself up on the smallest bump and bury the nose in the runway. Having the thing sniffing the dirt every time it hit a worm cast was not helpful for the acceleration and full up had to be held in to have even a chance of keeping the tail down. This didnt make takeoff very easy. 

 

In general thought once up the Harrow flew very well, it was just fast. At 66inches and nearly 11lbs it was just too heavy to fly at scale speeds and single engine operation was difficult as the rudders were very small. On one occasion he was trying to turn against the running engine and it spun, diving vertically towards certain death as it disappeared from view behind some tall grass and reeds. Imagine our surprise when an almighty plume of water erupted from the last known position! It was laser guided accuracy. Nailing a near 6 foot model into the middle of a 12foot wide stream in a field half mile wide. 11 points out of a possible 10 there! We found it floating on its back down the stream and fished it out with a willow branch. Only the canopy was lost, even the radio dried out fine and there was no damage at all. That must have been 25 years ago and yet i remember it like it was yesterday. 

 

Tipstalling on landing was a big issue although in fairness that might have be partly due to my Dad trying to land it like his other models instead of using the steeper approach i always try to use and recommend on warbirds today. His Harrow is still in the garage looking sorry for itself. I might steal it and see if i can get it repaired. 

 

The reason its sat looking sad is that every tip stall incident caused the wing to twist on the fuselage causing substantial damage. The design of the back of the wing meant it levered the fuselage apart breaking the model in half. The twist also stuck one of the propellers into the forward fuselage resulting in the nose being nearly severed as well. I think he just got sick of fixing it in the end. 

 

Maybe i should ask him if i can try and resurrect it...Might be a fun project and a bit of nostalgia for the both of us. 

 

 

[Paul De Tourtoulon]

Sorry Jon, but it never stalled on take off when it was electric powered, so probably too heavy on methanol,,,

[John Timmis]

Hi everyone,

thanks to all for your opinions, all are valuable & provide food for thought. It's a challenging project but the model came free & I have most of the stuff needed to finish it already in my spares so I think I will give it a go & see how far I get. It may turn out to be a one flight wonder but we will see.

The wooden bits weigh 4lb:11oz can't do much about that, add on a couple of motors  & lipos &it's up to 6lb 5oz. That seems to put the cg in about the right place but still have to add props, esc, paint etc.

At the moment I am doing the motor mounts & making a drop off undercarriage. I will post photos when there is something to show. Raising the ailerons is a good idea, it would be nice if I could mix some up aileron with up elevator but I don't think that's available on my transmitter.

I presume that the removable wing is a builders mod, it would have been nicer to mount the wing under the fuselage

Please keep the comments coming, it's all good stuff.

Cheers John

[Jon H]

Paul

 

The heavier the model the greater the required lift. You can generate this with either extra speed or greater angle of attack. Beyond a certain angle of attack the wing will stall. So if the speed was too low, angle of attack high to compensate, one engine perhaps pulling a little different, insufficient power to maintain the speed while climbing in that high angle high drag situation, it will stall. Had the speed been higher or the pull lighter, it would not have. As i have mentioned many times before excessive rates on elevator are also a big issue leading to excessive pitch when you dont need it. This could be as a result of instructions calling for excessive rates. Many kits are guilty of that, but the result is the same. 

 

Aircraft do not just randomly fall out of the sky be they full size or model. There is always a reason for it and one stands out above them all. 

 

I appreciate that you might feel insulted by the implication that it was a pilot error crash, but as almost all model crashes are pilot error its a fair bet given the circumstances. The heavy weight of the model would have reduced the margins of safe operation for sure, and in these cases it is very easy to make an error and it is very likely an error caused the crash as already discussed, but the weight was not the actual cause of the crash. To be clear, i am not trying to insult you or claim i am some sort of flying god who never makes a mistake. Like everyone i have made mistakes and damaged my models as a result. Its rare these days, but only because i admit my mistakes to myself and fly in such a way to try and avoid them. I also try to pass my experience and working practices on to others so they do not have to learn the hard way.

 

My intention here was not to be critical of you or anyone else, but to expose the likely reasons for the crash in the hope that preventative measures can be taken with this new model being proposed by our OP. Be that reducing the weight, washout, a different approach to flying, whatever. We have discussed them all and our OP will have more chance of a successful model because of it. 

 

Many aviation companies operate 'no blame' working practices and that is what i have in mind when i comment on things like this. 

 

I hope this clarifies my meaning an offsets any offence you feel. If you would like to discuss it further PM me so we dont clog up the thread. 

 

 

 

 

 

 

 

Edited September 2, 2021 by Jon - Laser Engines

[Paul De Tourtoulon]

No offence taken Jon, but I think that my crashes were due to a bad synchronisation of the engines,,

 I don't make pilot errors,,?

 

 

 Ps, I do put wash out on a lot of my planes for the first flights and limited aileron and elevator throws,,

[John Stainforth]

3 hours ago, Paul De Tourtoulon said:

No offence taken Jon, but I think that my crashes were due to a bad synchronisation of the engines,,

 I don't make pilot errors,,?

 

 

 Ps, I do put wash out on a lot of my planes for the first flights and limited aileron and elevator throws,,

 

Wow, you are tempting fate with a comment like that!

[Paul De Tourtoulon]

Yes maybe I will fly my twin Saito .45s powered Bristol Beaufighter to prove you wrong,,,

 

 It has been flying since April 2015, only 6 years,,?

[Jon H]

Its fine, badly tuned/synced engines count as pilot error anyway. Its not like they tuned themselves badly, and anyway rudder would have fixed that little problem so there is no escape ? 

 

My definition of pilot error is pretty broad, but i dont consider anyone a bad pilot until they make the same mistake repeatedly. Making a mistake is one thing, we all do that, but choosing not to learn anything from it again and again is another thing entirely. 

 

Still, 6 years on the Beau isnt bad. Im sure we all know guys who consider a model to be old if its lasted 6 months. Most of my fleet are hovering around the 8-10 year mark as things currently stand. 

 

I would really like a large beaufighter. Something around 80-100 inch span. I cant decide between that or a similar size mosquito. 

 

[Paul De Tourtoulon]

Stick to a big Mosquito there are lots of kits and plans out there,

 

 8-10 year old models, so nothing run in yet,,,?

Edited September 4, 2021 by Paul De Tourtoulon
photo

[David Ovenden]

Paul,

!t is a very nice Beaufighter. Flies well too.

Edited September 4, 2021 by David Ovenden

[John Timmis]

Paul, That's very impressive. Like it a lot.

[Paul De Tourtoulon]

There is a video on yooboob, under paulinfrance5