DH87B Hornet Moth

[Timo Starkloff]

Very interesting building thread, Martyn! And a good video, too!

I also thought about building a small scale indoor rc model, but it is hard to find information on the web (and finding the time for drawing/building + deciding what to build). Many from my new club fly indoor over the winter. My personal experience is from 1999/2000 with a self built 80cm Depron Cirrus Moth. Todays technique has improved a lot and I would also prefer wood for better looks.

Could you please provide pictures of the indoor scale event your building the Hornet Moth for?

Best regards,
Timo

[Martyn K]

Thanks Timo

The event is going to be held at in a hanger at RAF Shawbury at the end of March

I think this is fairly recent

best wishes

Martyn

[Martyn K]

Posted by Colin Leighfield on 27/01/2017 17:15:11:

The structure detail is getting close to full-size. Achieving strength by structure design rather than material mass. You really need incredible patience to do something like this.

Thanks Colin

Basically, I enlarged the 3v and drew my structure directly on top of the 3v. Even the wing ribs are not evenly spaced. Obviously some compromises, the inner fus isn't a plywood box like the full size.

Doing it this way has helped identify some of the traps I would have otherwise walked into. Sadly the (lack of) detail on the 3v hasn't stopped me making a few mistakes though..

Martyn

[Danny Fenton]

Just to clarify that video above is showing the smaller free flight area at Shawbury. The larger area behind the cameraman, is where the R/C competition will take place.

Malcolm's models fly well, but as they are profile depron would not do so well in the "scale" competition, they would lose heavily in the static judging, especially when viewed head on etc. But they would be very suitable for the "scale flying only" cattegory.

This video gives an idea of the other end of the hall....

Having designed and flown a model for indoor my oppinion is to work out the largest wing area you can go to and stay under the 200g weight limit. I think a 50" Cub is doable, and the wing loading would be very low indeed.

Cheers

Danny

[Colin Leighfield]

Martyn, it's going to be an impressive scale model regardless.

Danny, the Cub is looking well sorted now, you should be in good shape for the event. I can see your point about maximising the wing area combined with lightness. You've got me interested, I want to get home and see if mine will be viable or not. If it isn't I haven't got the time to dream up a bigger lighter one!

[Martyn K]

Unfortunately not much progress over the past few days. Family commitments and an afternoon flying blew out most of the weekend and working in London and submitting my tax return lost me another day.

The lower wings are now more or less complete.

I had to build the ailerons up - top and bottom so that they were flush with the cap ribs. That has taken two evenings - very fiddly and time consuming.

But they are ready to be separated. from the wing. Just a case or running a razor blade down the gaps.. and building up the courage. May practice on the rudder and elevator first

I also spent an hour or so getting all the radio bound to discover that the aileron channel on the receiver wasn't working. Top marks to Micron who changed it within 24 hours.. Excellent service

With the ailerons finished, I set the dihedral and built the centre section

The minimal glue I used yesterday morning was insufficient so I had to reglue it and add some extra gussets last night. So while that was drying I assembled the instrument console.

The layout was drawn up on CAD and laser printed then dye transferred to balsa

Then very carefully the holes were cut out and then reamed using a tapered reamer very gently.It then broke so I did it again - and again. <sigh>

I managed to get replica dials from a 1936 flight magazine advert, scanned and reduced them and printed on normal inkjet paper. I did consider photo paper to give a gloss effect but TBH I was just too lazy to redo them

SO after 3 hours of fettling and cutting countless bezels the console looks like this

My version with a photo of the original

and fitted this morning. Weight about 1/3gram

The last job this morning was to make a biplane.

Top wings are a bit droopy as no struts yet.Its also standing on its own undercarriage legs

Next job is to fit the lower wing (probably 2 x 10BA bolts) - add the aileron servo and struts and rigging and then I can think about access hatches and final detail and error corrections before covering.

The Esaki tissue arrived from Mike Woodhouse (Free Flight Supplies) at the weekend

More to come

Martyn

[Colin Leighfield]

It looks amazing, a work of art and extreme tenacity! You'll probably need to look out for wing warping if you are going to shrink tissue on the flying surfaces, but I'm sure that you'll manage that! Interested that you've made the engine cowl all in one piece with the rest of the fuselage, I'm looking to make mine separately and removable, again using small magnets.

[Martyn K]

Thanks Colin

Its certainly very different to what I usually do. Curiously, I am finding this quite satisfying. A total change of pace.

Already got an idea for next years Nationals if this works ok. That will be far more complex..

Access to the radio and motor bay has been a real head scratcher but I am going to keep a fixed cowl and nose block and use a hatch under the nose. If I need to replace anything like servos etc then it may need surgery but TBH if it survives the nationals I will be happy

Martyn

[Danny Fenton]

I have found the same thing Martyn, the change of pace, the smaller scale, it is most therapeutic. Not sure the Scale Column readers will agree. As much as I am enjoying all this small scale stuff, I think readers will want the larger mainstream scale modelling.....

Cheers

Danny

[Martyn K]

I am really looking forward to getting on with the Chippie now. I darent do anything with it at the moment in case I knock the Moth. I know which will come off worst.

Just thinking about a follow on to the Chippie now, Perhaps a 1/5 scale ki-43-hiyabusa for 30cc petrol

Martyn

Edited By Martyn K on 02/02/2017 11:43:11

[Martian]

Well. I am finding it fascinating

[Colin Leighfield]

Lots of interesting things here. I imagine that a major deterrent to building these small scale models is the limited weather opportunity to fly them safely outdoors and also limited number of venues to fly them in. With the miniature r/c and power kit that you can buy these days, they are certainly more practical. I've got some kits lying around, including a Veron Truflite Grumman Wildcat (18" span?), also a Guillows Douglas Dauntless and a Fokker Dr1, all good candidates for small radio and probably indoors.

Martyn, fancy you mentioning the Nakajima Ki43 Hayabusa, Oscar. It's been on my mind for some time and I've recently got hold of the excellent Marutaka Royal plan, which is 57" span and therefore about 1/7.2 scale? It easily provides a basis to build straight off the plan or scale up, even to do a Depron composite version, the fuselage sides in the full-size are an absolutely straight line from nose to tail in plan view, very simple to translate into a good scale model.

I continue to be amazed that this, one of the most important fighters of WW2 continues to be virtually ignored by modellers. Very similar to the Zero in many respects and certainly just as good on a version by version basis. About eight thousand were built compared to around eleven thousand for the Zero, but some references say that it actually achieved a greater number of kills than the Zero, I don't know if that's right or not. I have been thinking of starting a thread on it for a while. I wish that Tony Nihuis had chosen it instead of giving us yet another Zero, but that increases the incentive to do one. It definitely has to be done. Not being at Pearl Harbour doesn't disguise its massive contribution to the Japanese war effort and it deserves a lot more credit. Not well known is that after the end of WW2, the French Air Force used them in their war in Indo China, so you can even do one legitimately in French markings.

 

Edited By Colin Leighfield on 02/02/2017 14:04:13

[Martyn K]

This is what I will be working from. At 1/5 scale it will be 2m span. That short nose will suit the lead lined petrol engine I have. The Wikipedia article on this aircraft is a very good read

[Colin Leighfield]

Thanks Martyn, it is a perfect scale choice isn't it? The two bladed prop on the early models is great for scale accuracy as well. Very unusual on a plane that then did about 320 mph. I've read up a lot on this plane and you have a load of scale options, including the very effective manoeuvring flaps. Great subject. I also like the look of the later clipped wing versions.

[Martyn K]

Its got very good proportions indeed. Quite a long moment and generous tail surfaces. Should be nicely aerobatic as well

Getting very tempted to start drawing this up..

If I do I'll start a separate thread

Martyn

[Martyn K]

There are some incredible colour schemes to choose from as well

Martyn

[Timo Starkloff]

Good decision, I once built a Ki-43 and draw a plan. It flies really fine with the deep wing and the long fuselage. And the the wing shape combined with washout prevents tip stall over one side.

**LINK**

But back to the Hornet Moth, which airfoil do you use? I would like to try a thin airfoil for low reynold numbers and also flaps for better control of speed in small halls.

I like those small scale planes. Do you know these building reports?

**LINK**

**LINK**

Timo

[Danny Fenton]

Oo that's nice Martyn

Cheers

Danny

[Martyn K]

Thanks all

Timo - thanks for the links, I'll take a look later.

The wing section is a Gottingen 795 - or meant to be,

I know mine isn't as accurate as it should be. Apparently it needs quite a forward CG (20-25%) to make it work with about 4 degrees decalage

Martyn

[Martyn K]

A brief update from last nights efforts

Started fitting the lower wing to the fuselage. On the full size, the rear part of the wing sits below the fuselage. So last night I had to rework the centre section so it sits and blends with the lower fuselage

You can see the wing mount plates on this shot

and positioned.

Which has created another headache. I was planning on using torque rods for the ailerons. However I cant do that now they will exit the wing below the fuselage.. I need a plan B but I don't have one. I don't want to use bellcranks unless there is no choice. Too much slop at this scale

Other bits I did last night.

Added the handbrake and throttle controls

They look like knives in this shot but on the original they are polished aluminium - so are mine as well. Cut from a 33p baking tray. Don't use it for baking - its too thin

Also added the elevator trim control. I need to paint that gold

and the bracing struts within the fus - black tubing - in reality 1/20" square balsa painted with a felt tip pen. The anti glare panel is painted with GW Black paint - thinned with water

This morning I also added the roof panels ready for glazing

More to come

Martyn

[McG 6969]

Hi Martyn,

If I may allow myself a small observation as this splendid build will be entered in a scale comp.

In the picture of your OP - and following your 3-view as well - the 'black balsa' windshield fuselage bracing isn't joining in the middle of the windshield but a lot more towards the sides of the fuse.

... right, ok... I'll grab my coat...

Cheers

Chris

[Martyn K]

Don't worry about pointing out errors - there are many here and becoming more apparent as I try and assemble a 3D object from 2D images. Its quite tricky and I am grateful that people are taking an interest

I did wonder about the bracing location last night.

No matter where I put it, it didn't seem to match all the images I had. I never thought about the images I had already posted on here though.

I'll take another look

Thanks Chris

Martyn

[Martyn K]

Ah yes - I see what you mean. Thanks

Martyn

[McG 6969]

You're mostly welcome, Martyn.

As an 'apprentice', it's mostly quite embarrassing to point out an error in someone's experienced build blog in my opinion.

But apparently, if it can help you, this time I'm glad I did.

Cheers

Chris

[Martyn K]

Ihave now corrected the bracing struts - thanks Chris. All done by eye as they are not shown on the 3v.

I have been a bit stuck this week. I have hit the stage where I needed to for the cockpit before I could fit the lower wing mounting bolts and plates. I needed a pilot - required for flying points.

Meet Geoffrey, the son of Frankenstein's monster. Carved from pink foam and dressed in Jap tissue. He had three good points - he was light - 3g and the right scale and also a ginge..

He also suffered from a bad case of acne and what appeared to be 2nd degree burns.

So he was sent off for a bit of cosmetic surgery and came back like this.

Still 3g , had a hair transplant and still the son of Frankenstein's monster. (He is dressed as a golfer because the Hornet Moth was targetted at 1930's Golfing fraternity - had a stowage compartment included for Golf Clubs)

I needed a better pilot. Danny recommended a Dave Banks Pilot - specially designed for indoor models and a bust weighing only 2g. Unfortunately, I couldn't get one in a reasonable timescale (i.e. now), but Danny sent me an unpainted bust for me to use - very slightly smaller scale though..

So Geoffrey was sacked. Good pilot but too ugly

Which after 1st pass painting looked like this. (Wearing Suede trousers if anyone asks). Paint is Games Workshop Acrylics - perfect for this sort of thing.

A bit more detail and he was fitted:

and

This Cedric. Cedric is not wearing a flying helmet and goggles in a cockpit equipped aeroplane. The story is that Cedric has just arrived on his Brough Superior SS100 which is why he has still got his crash hat and goggles on. Strapped himself in then realised he can't find the keys so he is looking in his pockets for them. That will do.

Younger readers may need to Wiki Brough Superior and think Rolls Royce.

Thanks Danny, saved my life on this as I was stuck

With that done, the lower wing mounting plates fitted and a first full dry assembly..

Upper wing droopy as the struts aren't done yet (I need to build a jig to align the wings properly)

and

I can start covering the fin and tailplane and get them fitted then fit the servos and radio gear.

This is the beginning of the end

More to come

Martyn