Macchi Mc 72

So with any project thier is always a story. Many years ago when I was still a kid my dad's mate was building the most beautifull plane every made a supermarine s6b. I always said one day when I grow up I will build one. Fast forward 20years and this same mate has decided to trim down the his collection and one of them to be sold was the very s6!!!! So after having to make a plan and get the money together I am now the very proud owner!

Now for the tricky bit, as happens sumtimes, big scratch builds tend to become hanger queens and it happened in this case. After 20+years it still has not flown! The main issue is its on the heavy side with a wing loading of 46oz per Sq foot. (I believe it will be OK) but not wanting to take a chance, I decided I want to build a test bed but not wanting to end up with 2 s6b I looked for the best alternative. Finally setting on the macchi Mc 72.

I looked for plans but only found a smaller one that's rather old. So I have made a few more changes to bring it up to date and suit my needs.I also want it to be a add as you go type plane. I want to fly it in primer and add waight to get it to the same wing loading as the s6. So if it flys I know it will. Then I want to spend the time and make it to the same standered as the s6 is. I have made a start and gotten a fair bit done over the past month or so. It's a real tradition scratch build. Here are sum pics of the progress of where I am at the moment

Looking forward to seeing this progress!

I'm currently building a Schneider Cup racer lookalike: a David Boddington Sea Stormer.

I really like the sea stormer, it was in line and almost started till I decided on the macchi. Just a quick update from tonight's work I have started the turtel deck and have roughly shaped the horizontal. It's finally starting to look like a macchi and not a balsa cigar!!!

That's looking good. It's a much more complex shape than the Sea Stormer which looks crude by comparison.

I'm guessing it's a similar size? What engine are you planning to use?

The MC72 had twin engines in tandem, each driving one of the two props as a contra-prop pair. Himax in the US do tandem brushless motor contra-prop units in a whole range of sizes. They’re pricey, but perfect for this project. The lack of torque and spiral airflow on the fin would make water handling much easier too, as well as better handling in the air.

Byron is my son and has been dragged to the flying field since he was in nappies and grew up thinking that all garages were for model aircraft as well as cars as all the houses we went to had model aircraft in them. We spent many hours talking to Howard who built the S6 model and also of the visits to the Southampton museum to see the real one. Being South African this is not easy to do. I think these visits and discussions had a big impact on him and he now wants to give these aircraft a second chance like the DC3 that we repaired.

The Macchi will be flown with an ST 3250 as it will be about the best fit. The S6 was designed around a Laser 300.

The Solent Sky museum in Southampton is definitely worth a visit.

Here's some photos I took a couple of years ago. The first 2 are the full-size S6, the last is a model of the S4, I think. Apologies for the quality but I only had my phone with me at the time.

Byron,

I like what you have done so far, a very interesting project.

Watching with great interest.

Regards

Robert

Byron,

What weight and wingspan are you S6(b) and MC72? (I personally find wing loadings hard to relate to, unless I know the size. I prefer cubic wing loadings.)

I still have not flown my S6b, mainly because of Covid, even though it has been ready to go since mid-summer. Perhaps, next year, Covid permitting, those of us with Schneider models should try to organise a flying get together. I also have a Sebart MC72, which flies really well because it has a low wing loading.

Edited By John Stainforth on 01/12/2020 20:04:53

Nick Thanks for the nice pictures, bring back great memories. I went to the museum in 1993 when collecting a JPX from Ian Stockdale for a fellow South African Modeler as I worked for the National airline at that time. I had meet Ian when he came to South Africa to demonstrate the JPX at our Nationals. I spent the weekend with Ian and he had to work on Saturday morning as he owned Solent Models which was close to the museum. I spent a morning looking at the great aircraft and was surprised to see how small the cockpit of the S6 was and how large the Sunderland was.

That afternoon Dave Boddington came to have a BBQ with Ian and collect pictures and an article that I had done for the prototype of Dave's 1/4 Sopwith Baby. The next day we went to a large meeting at Wouborne Abby for Ian to show me how to start the JPX as he had problems with the starting in South Africa and only on his return did he realize that the density altitude in Johannesburg was causing the Propane to flow faster causing the motor to flood. The same starting pressure was also not spinning the motor fast enough so the excess Propane would freeze in the motor.

Byron was 3 months old at this time!

Interesting story, Chris. Altitude has a big effect on gas turbine engines (and other i/c engines for that matter).

Around that time I was working on the thrust ratings for the (then) new Rolls-Royce Trent engine. It was quite a challenge to achieve the required take-off performance at Johannesburg to meet the mission requirements without exceeding temperature or speed limits. It was quite common to incorporate a 'bump' rating around the altitude of airports like Jo'burg. Denver or Mexico City to promote sales to operators in those regions.

Chris you wouldn't happen to have any pics or details of your Sopwith Baby that you could share, perhaps in another thread?

A copy of the plan would be even more welcome! It has been out of print for many years and I would like to build one the DB way. If you don't still have the plan, then do you still have the model?

Thanks for any info you can give and back to Byron's MC72!

Alan the Baby flew for 20 years and was really a great flying aircraft, the only problem with it was that we did not fly it as often as we should have. 7 years ago our house was destroyed in a fire caused by a 2 cell 2200 lipo that was the receiver pack for a giant scale aerobatic aircraft. We lost all our stuff so no pictures or that plan but I do have the original pull out plan that could be enlarged. I can get it scanned and mail it to you if you send me a private message with your detail.

Nick Nice engines the Trents, you sure found the solutions with them.

I just recalled that this trip was also special as my mate was the captain so I was in the cockpit for landing at Heathrow which was also quite an experience

Hi Chris

That is a truly sad story - tragic really. I can't imagine how I'd feel if I lost all my stuff.

I do also have the small pullout plan, but I was just being lazy really as I know the bigger plan had details for removable wing panels and joiners. I've looked for the bigger plan for many years and I knew you had built the prototype for DB, so you were my only hope (like Obi Wan!).

Thanks for the offer of the smaller plan. I think I will draw up my own plan from scratch.

Evening all

The sopworth baby was a really nice flying machine.. It is on the list of have to do again.. It's been really nice to hear all the story's again as the last the last few projects have been memory lane trips for my dad and I. I also grew up reading the old rcm mags with the artical about the schneider cup shoot outs that they use to have in the USA. Would love to attend/participate in one But once again it's rather dificalt to try and aganize sumthing like that in Sa.

Jhon The s6 wingspan is 2.4m and the macchi is a 2.3 wing span. So it's about 1/4.

Back to the build. My dad has been tasked with the wing tips. And I have been sorting the tail feathers over the last week. This week end should be sum good progress as I want to finalize the wing plug in so I can close up the bottom of the fuselage.

Did not get all that much done but it really is starting to look the a racing machine

Evening all so a bit more work done this week. I have got the wings on and tubes glued in. Also got it all squared and in place now I can sheet the bottom and start to complete the building part of the project