My indoor Version

[Stephen Jones]

Hi ,

I thought i ought to give Depron modeling ago , as i have only used Depron in its simplest form before , But seeing Simon and others successfully build 3D models out of the stuff it was hide time i gave it ago.

And i thought this would make a good test subject as i have wanted to do a indoor version , but it would need to be very light , and the body is very curvy and so would test my ability to model with depron .

I must say for my 1st try at building with Depron in this way i am surprised at just how pliable it is .

I found that i can bend and stretch it into shape which has meant fewer strips on the body .

Giving a strong yet light structure ,

Lets see how it progress ,

Steve

[Dave Hopkin]

Lookin good Steve

I think you will start to really like Depron and maybe venture into it on a bigger model to explore its capabilities

[Tony Bennett]

Looking very very very good sir, it's going to be a great little flier.

Depron is the future of modelling.

i doubt i will ever build a balsa model again.

[Stephen Jones]

Thanks guys,

Done a little more on this one .

My pictures are not up to much as usual for me .

So far no real challenges here , i have just built it the same way i would if it was wood .

Now if i can make a model of this size and with its complex shape body there should be no reason why i could not build something bigger ,

Although i feel there are still things i need to learn about using this material.

For instance keeping the glue of my fingers which then gets every where .

The wheels are not to scale , but will have to do as this is for in door use , wheels are needed for take off , i do not fancy chucking this one around a hall ,

I have also made the wheels removable in case it proves not to be piratical for indoor use ,

I have the wing tips and ailerons to do along with the cockpit area .

Now my 24" outdoor version has a AUW of 200g so will be interesting to see how much lighter this one will be .

In my 1st picture the model weighed in at 49g and that is with two servos that are in the wings .

Steve

[Stephen Jones]

Ok ,

Radio gear in and tested ok , plenty of power ,

The radio gear is so small , i have been able to open up the Cockpit area .

I will have ago at putting correct size seats and pilots in place .

Steve,

[Tony Bennett]

now that is looking special Steve.

i do like the look of that model.

[Stephen Jones]

Thanks Tony ,

 

I have now made the plug for the Cockpit ,

I have not done much with it though ,

I am still considering on how to, and weather to do a Full cockpit detail and i seem to of mislaid my instrument detail i made for it .

 

Steve

Maybe it should be re-named my Micro Version,

 

 

Edited By Stephen Jones on 14/04/2015 19:39:45

[Colin Leighfield]

Looks like another winner Stephen, it will fly a treat.

[Stephen Jones]

Posted by Colin Leighfield on 14/04/2015 19:52:56:

Looks like another winner Stephen, it will fly a treat.

Thanks Colin ,

i am sure it will although i have not yet weighed it , it seems very light indeed .

Steve

[Chuck Plains]

Posted by Stephen Jones on 14/04/2015 20:10:42: i have not yet weighed it , it seems very light indeed .

Steve

It probably is light then.

Do I recall Simon Chaddock saying his 2.4 mtr span Libelle weighed just 11oz ?

[Stephen Jones]

I have weighed it , with out the wheels on and almost ready to fly , weight is 108 grams .

So i then weighed my balsa one of the same size and that is 170 grams .

In fairness the balsa version has a larger motor and prop, larger servos and larger receiver along with covering and carbon rods ,extra fittings.

Where as the Depron version has smaller servos , receiver smaller motor , no covering or paint , or cockpit detail as yet .

Steve

 

Edited By Stephen Jones on 15/04/2015 22:33:57

[Colin Leighfield]

Very promising, Simon will approve of that.

[Stephen Jones]

Hi again,

It is now ready for it`s maiden flight ,

Steve

[Tony Bennett]

very very nice.

bet it flies a treat sir.

[mightypeesh]

Very cute. Looks great, be good to see it fly.

[Dave Hopkin]

You sure you haven't been using Depron for years?????

Excellent......

[Stephen Jones]

Thanks Guys ,

I built this one for indoor use but finished it too late to try it at any indoor meetings ,

And with all this bad weather we have been having it still has not had its maiden Yet .

Yes, i have been building Depron models for Years , But only Profile models for indoor use,

This was a practice to see if i could build Proper 3D models for out door use .

Steve,

[Stephen Jones]

Hi,

When i got home today the sun was shining and the wind had dropped , so after My tea i decided i had better seize the moment .

So i took the little sipa out for a test flight in My local park where the grass is long .

Well my son did not want to come along and my daughter was also busy ,

So Billy no mates had to go on his own , when i got there i found they had cut the grass where i usually do my test flying and there was a keep fit class running all over it .

So i had to look for a more suitable place , which i found , a place surrounded by trees to act as a wind break and long grass to cushion the fall/ landing.

Well the good news it flies ,

Bad new no one to take any video and my attempt to clip on a camera to the side of my glasses only captured the ground .

It sadly needed more power so i could only just manage half a circuit before the ground came up to meet it .

So i will fit a bigger prop and try again ,

A least i know it flies and the soft grass makes for a nice soft landing .

Steve

[Stephen Jones]

Hi ,

I finally managed to Test fly this one tonight.

I bought a pack of five Props that looked ok they are smaller than the one i previous used but the blades are wider and have a greater pitch.

I used my keychain Camera mounted onto the side of my glasses to record this video.

Steve

[Stephen Jones]

Hi ,

I have decided to convert this one to EDF.

So after some testing i have decided to use the AEO 13000Kv EDF unit .

As you can see it is small 30 mm Fan unit which will run on a 2s Lipo.

So i have removed the A1504 Motor from the rear of the Model.

In a small way i was disheartened by doing this as it is a perfectly good working model just not practical for indoors.

[Stephen Jones]

I carefully opened up the hole.

As you can see the hole is smaller than the Edf unit so i made a simple duct to go around the Edf which is reduced down to fit the rear exit of the model.

And just for comparison i stuck my finger in the hole.

The next task was to open up the Air intakes .

Steve

[Stephen Jones]

Opening up the Air intakes.

As you can see their is plenty of room for the EDF unit.

Steve

[Colin Leighfield]

Looks promising!

[Simon Chaddock]

Stephen

That looks very nice.

With these small very light Depron structures it is amazing how simple (almost crude!) you can be.

Part of the secret is with very thin Depron sheet structures is the glue, once hard, is as strong as the Depron so you can open the structure up, glue in a new piece and its as strong as was.

Of course the same goes for repairs as well.

Are you just 'letting the air into the fuselage' rather than using inlet ducts?

It should work but either way don't scrimp on the inlet area.

The combined area of two small inlets does not equal that of a big one of the same area. In addition these tiny fans are much more sensitive to inlet rather than exhaust restriction so the inlet should be at least 1.5 times.the FSA.

Then there is the exhaust tube.

Just imagine the duct area as you move away from the trailing edge of the fan itself.

It starts at FSA (obviously) then the air meets the motor bell which in the case of these small fans narrows it down by about 15%. At the end of the motor bell the duct area suddenly increases to about 1.5 FSA.

You can only imagine what the air is actually doing at that point. The rule is its is easy to slow air down in a duct (it does that by itself!) but it is much harder to speed it up again efficiently. Regardless the mean velocity of air in a duct is proportional to the cross section area and its the velocity at the exit nozzle that creates the thrust.

This why I adopted a 'fan at the back' philosophy if at all possible. The end of the fan shroud becomes the nozzle and the air leaves at what its speed is.

The twin 40 mm EDFs right at the end of the long duct on my Concorde.

As the Sipa fuselage is plenty big enough I would suggest you do the same.

[Stephen Jones]

Hi Simon ,

Thanks for the advice, i guess i should of looked at you're builds 1st.

I have fitted my EDF into the Sipa with a 7 cm tube which reduce from 30mm to 25mm i think i should be ok with that.

Not only that i do not want to open up the rear end of the model any more than i already have.

I could move the EDF Unit further back than it is at the moment but i feel that the sharp angle of the duct from 30mm to 25 mm may slow the air flow down considerably more than it is now.

I may make the air intakes a little larger than they are presently. I was hoping to test fly the model outside today however by the time i got to the field it was too windy and was getting stronger and changing direction .

So i did not get any flying in at all today. The sad thing is that there was a indoor meeting on today i could of gone to .