Martin Baker MB 5

[Chris Freeman 3]

Last year my son and I were looking for a project for a counter rotating prop unit that was built for his Maachi but not used as the aircraft was finished and flwn before the unit had been completed. The one aircraft that seemed to fit the requirement was the MB5. I had 2 old Scale RC Modeler magazines from 1979 that had quite a bit of information on a model and how well it flew. The internet provided more detail and 1 very interesting 3 view showed a Mustang and MB5 superimposed and that made up our minds to build one.

I got my Top Fiite 1/5 Mustang kit out and made changes on the plans and used the kit fuselage as a template to cut out my own parts. Wings and tail feathers are foam and veneer. Not superscale but good enough to see for us what it is, many will think it is a clipped wing Mustang!

[Simon Chaddock]

A very impressive build.

I note you have included the fabric covered rudder. The only such material used on the whole plane!

It is remarkable that the modest Martin Baker organisation managed to produce such a remarkable and practical fighter.

Given it was only ever experimental and flown by test pilots it does seem a pity that it was not kept but ended it days as a target on a firing range.

What prop will it have?

It does look much better with scale diameter three bladers. 😉

Indoor, electric and control line. 24" span it weighs 4.5 oz (128g). Built 55 years ago. I still have it but now firmly retired.

 

 

[J D 8]

    Formed by James Martin and Captain Valentine Baker Their MB series of development were quite remarkable. 

Baker was killed test flying the MB3 when its Napier Saber failed.

  The MB5 was a development of the 3 with simplified construction and Griffon engine with the contra prop. Ground crew were complementary as to the ease servicing could be done.

[Chris Freeman 3]

Nice Model Simon. Props are a problem as the front on is a pusher prop on the unit we have which currently has 23x 8 props as that was what we could get as a matched pair. Test flights will be done in primer and with a normal drive electric motor as I would hate to damage the counter rotating unit that has taken lots designing and machining done by a friend of ours. The airframe and detailing was done by Byron who stays 6 houses down the road and I will do the installation for the test flight. The fuselage has a  motor box that will make motor changes easier and a hatch on top of the fuselage for easier battery changes.     

[Simon Chaddock]

Wow! Are you really planning that rivet detail?

 

As I was using high revving Scalextric 12V motors they had to be geared. They already had small pinions fitted so I took a guess at the overall ratio to turn the 8 inch scale props. I was fortunate that my Dad was a true model engineer so he cut me a pair from a high strength aluminium and turned up the appropriate hubs,

Steel shaft inner with ally tube outer. The steel inner ran in a brass bearing at the motor mount, The outer ran in a split plastic bearing right behind the props.

The result was quite a neat contra prop setup.

Of course only a tiny power output by RC standards, about 50W in total, but it did mean I could carve my own "inserted blade" props from medium hard balsa.

The only disadvantage was that the high revving straight cut gears coupled with a "sounding box" hollow wood airframe meant it sounded like a turbo prop in the air.

In principle at least a "beefed up" version could create contra props using unmodified brushless motors. 

[Roy Thompson]

Good luck with her Chris, she should look excellent when finished. Of course you will need to get used to people asking if it’s a Mustang !

 

Re the issue of pushers props, I use the Ramoser varioProps from Germany for all my contra motors. They do a good range of tractor & pusher props that are ground set for pitch. This makes them very flexible to suit your motor.

 

Now the important question; how many watt’s, cells, span and whats the AUW going to be?

 

Good luck, and keep posting the pictures 👍

[Chris Freeman 3]

Simon and Roy

I love the pictures of your aircraft, both are a credit to you. The MB 5 is progressing well, retracts are fitted and working and even holding air for more that 24 hours which is great but I need to see what they actually do at the flying field! I am not sure what the weight will be yet as I often find the pilot and airframe fly better when they do not know that they are heavy! the length is 190cm with the spinner. The motor I have fitted is a EMAX 5335 which will use a 19 to 22 inch prop. The Motor on the drive unit is a EMAX 5345. EMAX do not give any performance detail other than prop size and recommended weight. All servos and pushrods are fitted so we hope to test fly in about 2 weeks time. I will be doing some tests to find the best prop to use.

 

Thanks for the info on the props but being in South Africa means it is very expensive to get stuff due the the exchange rates and courier fees. I am a bit of a cheap modeler that gets a lot of my stuff second hand as Byron and I are always busy building. We also mainly fly early morning at our own field so the aircraft are not display aircraft. We were invited to a club on Saturday and our 4 aircraft were the only own constructed aircraft! Scratch building is really dying in South Africa      

[Roy Thompson]

Scratch building is an endangered pastime all over, but sounds like you’ve a few more challenges.

 

I was wondering if you’ve come across this forum by Nick aka Mr Smoothie on RC Groups. His was built to the same plans as my own and he decided not to go the contra route, as he quite rightly points out; the motor assembly then becomes a project in its own right. 

 

Nicks finished model looks fantastic and between all us MB fans there is an amazing amount of information here, enjoy 😀

https://www.rcgroups.com/forums/showthread.php?4163253-Martin-Baker-MB5-1-7-6-scale-Dan-Parsons

[Chris Freeman 3]

Hi Roy

Thanks for this information, I will spend some time reading it. The Article that inspired this build was by Dan Parsons! The retracts sure are a challenge, I wish I had mounted mine further forward in the wing, mine are close to the scale position and are limited to the spar position that I used. 

[Chris Freeman 3]

Starting to look like an MB 5! First time on its wheels. 

[Chris Freeman 3]

I am glad to report that the test flight went very well, very nice flying aircraft with plenty of power. We are using 12 cells and a 20x10 prop and are getting 2300 watts with an all up weight of 8.7 kg. Some clever person decided to do donuts on the runway in his car which did damage the ground but as it has been very hot it was not that bad. Some aileron trim was needed and that was all so the airframe can now be painted. My building skills are luckily better than my video skills so here is a poor quality video that shows just how comfortable Byron was with the flying qualities:  

 

[Martin Harris - Moderator]

I’d love to see that video without the music. Some excellent flying!

[Eric Robson]

2 hours ago, Martin Harris - Moderator said:

I’d love to see that video without the music. Some excellent flying!

Turn the sound off  Martin, I did 

[Chris Freeman 3]

Byron is doing some work on the airframe and has done the exhausts on the 3d printer and also working on the canopy. We plan to fly it again and then strip for painting. 

[Chris Freeman 3]

More work done. 

[Chris Freeman 3]

Work is continuing and Byron has 3d printed a pilot and been working on the cockpit detail and I think it looks good. We did have another 2 flights with it and it is a very smooth flying aircraft. We hope to start spraying this weekend so I hope the next post will have some colour to it!