Harmony build blog

[Peter Miller]

Dear Twinstar. I never write about anything that I don't know about and I know absolutely nothing about electric power. I would not have a clue what size of motor or battery or ESC to use.

 

 Therefore I am afraid that you will have to ask someone else. I am sure that any serious electric flyer could look at a model and, taking weight and size into acount say exactly what moroe to use just as I could look at any electric powered model and tell you what i.c. motor to use.

 

Sprry that I can't be more helpful

[Peter Miller]

Don't worry, I didn't take it as a personal dig.

 

If I don't know something I am very happy to admit it.

 

That was an explanation for not putting to info on, not an excuse or apology.

[Jimbo565]

Peter,

 

This is the cabane assembly on the Toot,something like this may be adapted for Miss Lizzy.

 

Two bits of 1/8 ply run along the top of the fuz sides and the cabane struts are bolted to it.

 

Jim

[Peter Miller]

Ah yes, I was thinking of a splayed cabane.

[Tony H]

Hi everyone this thread is very interesting. I have the free plan which comes with the RCM&E Magazine (June 2010). The Harmony looks great! and just what the doctor ordered. I am looking to build the plane but I find it a little awkward to know what materials to buy.

 

Please can you help? maybe you could give a breakdown in list form of all the materials required to build the Harmony so I know what to buy. I am planning on building the plane with a SC25 aero IC Engine, hopefully that should give it a good amount of power. I am currently flyng the ARF Blackhorse Travel Air without much difficultly how much different will the smaller Harmony be to fly?

 

Any help would be appreciated, thanks.

 

Tony

[Jimbo565]

Tony,

 

To list all the parts needed to build a model you would be on till xmas,I build one part at a time eg. the fuz then the wing etc.buy the wood for the part in hand and you wont get bogged down.

A model like Harmony from start to finish will cost around £100,all the little things like tank/wheels/snakes/clevis/hinges/motor mount /covering material soon put the price up.

 

My Harmony has SC25 power and it goes like a dream and if you have low wing experience it should be no problem.

 

Cheers

Jim

 

[Peter Miller]

Two or three years ago I wrote an article on estimating materials for a model.

 

Perhaps the editors could put that on the website because it is obviously something that is needed on a regular basis.

 

If you can fly the Travelair then harmony will not be a proiblem but be away that it will get small quite quickly, not a problem but something to get used to.

[Tony H]

Thanks guys

 

Jim,

 

Did you put a 4oz tank in your Harmony as the plan suggest seem's a little small for a SC25 to me, if you did how many minutes have you had flight time from it?

 

 

[Jimbo565]

Tony,

 

I have a Slec 4 oz. tank in mine and can get around 10 mins.out of it but thats not batting it around on full chat all of the time.

Its a geat little model but as Peter say it gets small very quickly so be on your toes.

 When she is banked up in a turn she looks like a Spitfire,If the correct canopy was fitted and a camoflage colour scheme applied it could be a Spitfire.

 

Jim

[Tony H]

That's good then I usually land at around 9mins to be safe. I was thinking of doing a sports plane/car colour/sponsers scheme. something like gulf colours. What do you think?

[Jimbo565]

Tony,

Go for it my man,there aint any rules when it comes to colour schemes.

Jim

[Peter Miller]

Don't worry about going dead stick, she glides very nicely too.

 

Yes, a fancy racing coliur scheme would look sensational.

[Tony H]

If I was thinking about painting the plane when I have built it what sort of covering would you recomend?

[Jimbo565]

Tony,

 

I used Solartex to cover mine with minimal trim,Solartex takes paint  very well although there will be a slight increase in weight as against profilm / solarfilm.

I normally use profilm to cover my models and it also takes paint ok,bear in mind that if you use paint it will have to be fuel proofed which adds more weight .

 

Jim

[Tony H]

Surely the paint won't add much weight....will it? not enough to effect the model much, especially with the SC25 in it?

[Tony H]

Also, I know i'm not there yet but could you tell me what throws you have set your planes alierons, elevator and rudder to so I have a starting point when mine is ready to fly? Thanks guys

[Peter Miller]

I assume that you have the article with the plan. If you look at the section "Tasty With a Twenty". At the end of that section it gives my control throws.

 

On the subject of weight. Not only is the power to weight ratio important and, in the case of using the .25 you have plenty of power, What is even more important is the wing loading.

 

Put very simply, light models fly much better.

 

To give an example. My 73" span Falcon semiscale Fournier would fly aerobatics very gracefully, it weighed 50 ounces. What always stunned people was the fact that it flew so well and would do loops and rolls and inverted and combinations on these on an SC 10. Yes, 1.5ccs That was because of the low wing loading. The power/weight ratio had nothing to do with it.

[Tony H]

So do you think the harmony could take a Solartex covering which has been painted or do you think it would be lighter with a solarfilm covering with some solartrim to make the desired colours.

I was thinking of orange under the wings and fuselage with a gulf orange stripe down the middle of the fuselage from nose to tail with the rest of the planes sides etc being blue.

What do you think would be the lightest and best way to achieve this?

 

 

[Jimbo565]

Tony,

Film with trim will be lighter than Solartex with paint and as Peter has said lighter the better.

 

The model will certainly take Solartex and paint and fuel proofer and it will still fly well on the SC25.

 

JIm

[Peter Miller]

As Jim says, Film and trim will be lighter but it will still fly OK.

 

The effect of extra weight is to slow down the model's top speed and also raise the stalling speed.

 

However if you don't go mad on the finish you would probably not realise the difference unless you flew my light one at the same time as a heavier one. A couple of ounces will not make too much difference.

[Tony H]

Thanks guys,

 

Do you think a painted tissue and dope covering would work well, or do you think it's a little old fashioned and weak?

 

 

[Peter Miller]

Tissue covering on the wing would be liable to split and tear easily.

 

Dope and tissue over the wood of the fuselage would be fine. You can achieve a reall Rolls Royce finsih that way but it does take a lot of patient work for a concours finish.

[Tony H]

Thanks Peter, what do you think of using SIG Koverall to cover the plane then paint that?

I have to say looking at the plan the main wing does look quite complicated compared to build kits I've built 

[Peter Miller]

Never tried Sig Coverall so can't comment.

 

Yes, it is a bit more complicated but if you follow the sequence in the instructions you should have no trouble.

 

Really it looks more complicated because of the inset ailerons and the shape.

[Tony H]

Thanks Peter,

I don't fully understand what is mean't by the 1degree and 2degree wash out on the wing? does it meant I have to sand the wing to the same angle and thickness as the two washout drawings on the bottom left of the plan?

 

Also what servos would you recommend Std servos look quite big for this model, and I have read that Hitec Micro  HS-81's strip gears easily, I was thinking maybe two Metal Geared HS-81MG for the Elevator and Ailerons and maybe two HS-81 for throttle and rudder?