Nice job on the CAD drawing, Alec. I find the time-consuming bit is thinking through and drawing in the structure, and yet there are still bits I can't imagine in 2D and have to figure out by prototyping.

Steve

Haven't got to playing with structure yet Steve, but I have no doubt that weeks could be made to disappear! Working in foam, my immediate needs were the wing and fuse outlines at full size to make templates. I had hoped to start cutting this week, but the largest insulation distributor in the UK has refunded my order for XPS this morning, as not prepared to bring it into stock locally.

Nevertheless some considerable progress has been made in considering the airframe geometry over the past few days. John (RPFJ) has been a great help with reviewing the available drawings and plans. There's quite a story there and we will write it up soon.

Starting to think about layout and hardware requirements. Despite the size of the fuse, accommodating the batteries doesn't look like a viable option, because of the wing centre section and the cockpit. Its looking as if a motor, battery and ESC will be housed in each nacelle. But there are advantages too. With the receiver positioned on top of the wing, I will only have two servo connections to make when the model is assembled at the field.

Take care with the shape of the nose and fixed part of the canopy. Most 3-views show this slanting upwards towards the front, which it is definitely not when looking at photos of the real thing. Plastic modelers rant about this extensively. Great project, I have the Cyril Carr plans which I hope to get to eventually. He puts the batterys in the radiator area of the wing between fuse and nacelles.
Lorenz

Over the past two weeks quite a lot of time has gone considering the options for the wing design. Building the Hornet presents a distinctive challenge insofar as:

• there are no surviving examples from which a conclusive measurement could be made.
• there is some really interesting period documentation, but I haven’t been able to find a definitive wing drawing or reference to the wing section.

So while there are a number of published drawings and plans of the Hornet, it is likely that the authors of most of these will have been working with imperfect information.

Against this background there have been two strands to the research:

• appraising the available drawings and plans.
• developing a wing section on an iterative basis starting from a photographic reference for the wing mid-section.

In both of these I have been hugely helped by John (RPFJ) and I would take this opportunity to thank him for his contribution. I’m not sure how much sleep he was getting earlier this week.

Review of the Available Drawings and Plans

John spent considerable time analysing the available drawings and plans, the section information they contained, and their viability as a basis for wing design. In conjunction with the supposed wing section, he also looked at the relative rigging angles of the wing and tailplane and considered the implications for flight characteristics:

• of the three views examined, the drawings by Richard Caruana were considered to have the greatest consistency with the photographic record and to be representative of an advanced aerofoil design of the period. The wing and tailplane rigging was considered to be internally consistent.
• an Air Ministry technical drawing was considered to be aerodynamically viable, but to be based upon a conventional section such as RAF 34 or 38 rather than the more advanced section actually used in the Hornet as indicated by the photographic record.
• of the model plans reviewed, that produced by Geoff Whitehead was seen to be reasonably consistent with the actual layout of the Hornet. However the wing section was seen to be a conventional flat bottomed type and to be rigged at a lower angle of incidence than the original. While considered viable for a flying model, it was considered that the arrangement would be likely to produce a more “nose down” attitude in flight than the original.

Developing the Section

The clearest indication of the actual section used in the Hornet we have found is from photographs of the Sea Hornet with its wings folded and which confirms it to be a laminar flow design rather than the more conventional section used in the Mosquito, for example.

Taking account of angle of observation, John derived a first pass estimate of the section from the Sea Hornet. Thereafter, I developed a series of iterations around it, firstly taking account of perspective, and thereafter drawing on the essential geometric characteristics of laminar flow aerofoils. John commented on the drafts and through a process of iteration we arrived at a section that John believes to be aerodynamically sound and which I think “looks all right”.

Overall

There are various possibilities for wing design which will allow a viable flying model. There are pros and cons to each and “you pays your money and takes your choice”. On balance, we see advantages in applying something close to the original deHavilland geometry to the layout in the Caruana drawings.

Anyway, enough talking. It’s time to cut some foam.

Hi Lorenz

Thanks for your pointers on the canopy shape. I'll have a good look at my photo collection.

We haven't seen the Cyril Carr plans, but agree it is sensible to allow flow through the radiator ducts. I envisage using it to cool the batteries and ESCs.

All the best

Alec

My available time this weekend disappeared learning how to scale in CAD and size for printing, but its all interesting stuff and nice to find there’s still something new.

Next fun will be making up templates and cutting out the foils.

Alec, very glad you've said it is EPS foam. middle pic makes it look like marble, so thought you must have been pop-eye or superman to cut it out. think there is something about the sea hornet in this month's flypast if you've not seen it already.

[QUOTE=fairweatherflyer;33324175]Alec, very glad you've said it is EPS foam. middle pic makes it look like marble, QUOTE]

I suppose in the world of EPS, she's not exactly Claudia Schiffer (giving my age away there). I looked through all the sheets to find the best piece. I thought I would save the white end for sculpting. And you are quite right. I kept losing the outline points I punched through the tracing. Yes. Sooner its sheeted, the better.....

Will check out FlyPast. Always good to read on the train.

In order to work in a little washout and a little vertical section taper, the wing core was cut in four sections. This also enabled me to use my 20cm bow and to work indoors. The relative position of the sections was maintained so they will be able to lie in the beds when they are glued together and when I insert the spar.

Looks good from here.

J

Hey Alec,

Your and John's forensic aerodynamic adventures are fascinating. Being a "that looks about right" aerodynamicist myself, I get a little shiver of anxious excitement whenever I see someone take a more deliberate approach.

Judging by the size of your drawings, I can already see that yours is going to be one of those builds I show to my wife the next time she complains about how much room my hobbies take. "You see dear, it could be much worse...". And your workshop will be helpful in that regard too.

I'm going to have give hot wire foam cutting a try one of these days...

Steve

Thanks J. But then you are quite a long way away!

Steve. Glad to be of service. It is turning out to be 1:8.7 scale - 62" span. When I was at the printers I got them to apply the overall length to the fuse drawing, forgetting that the spinners stick out ahead of the nose. So picture the scene at the LHS " Excuse me sir, do you happen to have any 1:8.7 pilots in stock .....

You will just have to go for the classic crew of any combination of 'Lofty' &/or 'Shorty' . Good to see the wings coming along.

Yes. You may remember the malnourished crew that came with the old Airfix kits. Yet you read that aircrew got all the available bacon and eggs...

Been starting to look at undercarriage dimensions and angles. Scale retract angle is coming out around 110 degrees. Not much on offer for this size of model.

Hi Alec! Merry Christmas!

Found your thread quite by accident. I was Googling the Sea Hornet and found it listed. I'm building my second warbirdkits Hornet, and decided to make it into the Sea Hornet. Like You, I prefer the vertical without the dorsal. The proto with the camo/yellow bottm will be the choice. The one you have piced earlier.

I have an old thread on the kit from 11 yrs ago. I missed this plane a lot. It was one of the best flying planes I ever owned. I sold it to a friend in west Connecticut in 2005. It was destroyed by a LiPo fire. https://www.rcgroups.com/forums/showthread.php?t=289258

There were no outrunners back then. This one will be a much lighter version. I have 3 pairs of different outrunners I can use, of various sizes. So I'm covered for power choices. As it is only 39"WS, I'm able to build it in the living side of my home. My shop room is under-going revamping. It will be ready by the time I need to paint.

I'm contemplating making light built-up airfoiled tail surfaces, instead of the solid surfaces. The fabric surfaces just appeal better. And I can usually get them lighter than solid.

I'll check in on your progress. Good luck!

Fuzz