Orion-E electric glider build blog

[David E]

Oh, and weight shouldn't be too much of an issue as the airframe is designed for a speed 400 motor and nimh pack. I may end up having to ballast the nose anyway!

[Andy Gates]

Dave

 

Can you do me a huge favour?

 

Can you measure and post the overall diameter of your prop & spinner combo please?

 

Cheers

 

[David E]

Andy, it's 6.9". I'm hoping to change the spinner to one from MP Jet that's a better fit for the blade roots but I think the overall diameter will be about the same.

[Norman Wyatt]

David

 

Many thanks for the info...I'm sure there will be more questions in time.

 

Kind regards.

 

Norman.

[Andy Gates]

Here is a little prediction I have from the info I added to Motocalc using components as close as I can get to those you are using.

 

Estimated complete model weight 14.3oz

Max input current 9Amps

Input power to weight 58.5w/lb

Thrust 10oz

Pitch speed 32mph

Run time 1min 40s

 

Stall speed 11mph

Optimum speed 14 mph

Rate of climb 520 ft/min

 

That makes it do able but I would suggest that you do a full throttle test prior to flight with a watts meter just to test the full current capabillity of your set up.

[David E]

Thanks Andy, all useful info.

 

I've ordered a pair of blades of each of the smaller sizes so that I can pop round to a friend with a Wattmeter and test out all the combos in one go. Will post results here when I get to that stage. Still waiting for Puffin to get those spinners in stock. They said about a month a few weeks ago, so I'm hoping it won't be too long!

[David E]

The 5.1x3.1 blades had turned out to be pusher blades   As I don't know which spinner I'll be using yet I don't know whether this will present problems or not yet. Ho hum!

 

I phoned Puffin Models again to see if they had an estimate on when they might get these in stock but they don't think it'll be this year at least, and no real estimate of how long it may be They did at least mention Fanfare who also stock a limited range of MP Jet items, and they had a different spinner from MP Jet which sounds like it should work. Will have to wait and see!

 

How much am I going to end up spending just to get a propellor that works on this plane?! Still... I suppose the box full of spare bits may come in handy for future projects!

 

Still making slow progress on the airframe. I've prepared the servo rails but not fitted them yet as I'm unsure where I want them, as it will depend on the C of G. This depends on what spinner I'm using! :-s I also need to sand the hatch cover to shape to get some idea of weight distribution. I'm planning to lighten the tail section by using a built-up construction, too, but again, this is on hold till I have more idea about C of G.

 

I have nearly finished the wing except for the lower sheeting on the outboard sections and, of course, the covering. I hope to use Fibafilm as a clubmate reckons it is the best stuff to use on Orion wings due to the light build.

Edited By David E on 09/11/2009 14:08:21

[Andy Gates]

David

 

I have used and still use Graupner folding props and personally I like them.

 

Either buy the whole prop together or get the spinner/mount and blades separately.

As you probably found out, the thickness of the blades needs to match the hub dimensions.

 

I get mine from either Galaxy Models or Sussex Model Centre.

 

Personally I like to mix and match so I get separates.

For blades I like the carbon ones which seem to bite the air nicely without bogging down the motor.

A 7x4 looks to be available or a 6x3

 

With a gearbox or low kv motor, get the geared blades. They bite really well but too much for normal motor use.

[Norman Wyatt]

David

 

Wings and fuselage are made up and nearly ready for covering.  Being my first effort at building could you share your experience when you get to covering your plane.

 

I have really enjoyed the build and would like to finish with a reasonable covering.

 

Norman

[David E]

Norman, I'm afraid I haven't started on covering mine yet, still quite a bit of work to do on it first, and lack of time makes for slow progress. I'm also probably not the best person to ask - I've never used iron-on coverings before! I only have some limited experience of tissue covering.

 

Have you got any pictures of your build?

[David E]

Oh, and I did finally get an MP Jet spinner from Fanfare, which seems to be a perfect fit for the blades and motor shaft, and the right diameter for the fuselage, though I haven't built the front section yet.

[David E]

In case it's of interest to other people, I weighed the electronics set-up I'm using:

 

Comes to 88g in total, not including the prop.

[Norman Wyatt]

David

 

I will worry about the covering when the time comes, still plenty of jobs to do.

 

I took some photos but they do not add anything to the ones that you have taken.

 

Norman

[David E]

what power setup, servos etc have you gone for? Also curious to see how you do the motor mount. What colour scheme do you think you will do?

[Norman Wyatt]

David

 

Can't help on many details yet.  I am finding the range of motors and ESC's overwhelming.  Making a choice is difficult as the more I look, the more I see.  As the old saying goes, 'I used to be indecisive, but now I just can't make my mind up'!

 

I will probably welcome suggestions from someone with more knowledge than me, which just about includes anyone.

 

I am semi retired and money is a big issue as I am trying to do everything on a limited budget.  There is no way that I can spend without getting value for money.

 

My outfit will be a low budget basic unit.  I will get fun out of it which is the main issue and building the plane has been really enjoyable.

 

 

 

[David E]

Yeah, the whole prop/motor/ESC selection thing is a major headache, isn't it? The thing that's really frustrating is that most of the motor calculators I've found only provide info for expensive motors, or require you to put in constants that I have no idea how to measure The best approach seems to be to either find someone who knows a lot about it, and copy their set-up You could go to a local shop and get them to recommend a setup, but you won't get the best value that way, which is to be had from Hobby King!

 

I'll let you know how I get on with my setup once I've got a Watt-meter on it, but do be aware that it requires some nose modification to mount the motor (still working out how to do mine). I have only chosen this motor it as it's mandated by the rules of my club's duration competition. The glider might benefit from a motor that will spin a bigger prop (lower kV rating on the motor), as it will be more efficient. However, I've heard that the Orion-E doesn't climb nicely under excessive power, so be cautious about getting something too powerful. It's designed originally for a brushed 400 motor, you might consider this, as the motors are certainly cheap! They are less efficient than brushless though, and heavier. Also, finding a brushed speed controller in stock at a good price can be tricky.

[Tim Mackey]

Well without studying the whole thread, and criteria required ( did spot something about comp rules somewhere ) I would have suggested a different type of motor to the one in the first post.  A 2100 Kv motor is too high revving  IMO for what is basically a glider.

The fact that the model was originally designed around a speed 400 motor is a red herring - this was just because the speed 400 was about the only thing available - ideally a slower revving motor swinging a larger prop would have better, therefore with the vast choice of motors available these days, exploit their characteristics and choose a lower Kv to swing a larger diameter prop at lower revs.

Quieter, more thrust, and more efficient.

[Tim Mackey]

I rather think David and I simu- posted there

[Norman Wyatt]

As it is pouring with rain and I have just returned from a walk up the river (to watch an Otter hunting) and I am as wet as the Otter, I will spend the next couple of hours searching for a motor ect.

 

It is too wet to shape and sand the front balsa block as I only do this outside, so has to be dry.

 

Not too bad as it forces me to keep away while the wing glue is setting.

 

I noticed in your profile photographs you have a Fox set up for R/C as well.  When I bought the Orion, I picked a Fox up as I left the shop, a bit more fun to be had once the Orion is finished.

 

Norman.

[Norman Wyatt]

David

 

Just found this site relating to coverings.  Seems helpful.

 

Giantcod covering.

 

Norman

Edited By Phil Wood - Moderator on 16/11/2009 13:46:28

[David E]

Thanks for the covering link, that looks helpful. I need to buy myself a covering iron from somewhere. GC's one is out of stock Might go to Hobby King.

 

I'd leave sanding the front block until you have got your motor and prop, including spinner, as you may find you can't find one exactly the right size, which may necessitate modifying the countours at the front. Depending on the mounting of your chosen motor, you may need to do some more major modifications, as I will have to.

[Norman Wyatt]

Oop's...rain stopped so I went outside and sanded the block, I can always re-do the block if need be.

 

I saw the covering from Hobby King and it look good value.

 

Norman

[David E]

Check the reviews for products on Hobby King. They are usually useful to decide which products are good quality and which ones aren't! Do be aware of postage and taxes though. If you keep orders under £18 then you are not liable for VAT or duty, and it isn't usually more expensive shipping wise to split orders either.

[Norman Wyatt]

Thanks for that tip...I think I'll give them a try.

 

I tried to download some photos, but the system didn't like it.

 

Norman.

[David E]

Doh Doh Doh!

 

Schoolboy error!

 

 I thought about the current limits of the motor and the ESC but not of the battery! I'm not used to working with restrictions on batteries, certainly not on batteries this small!

 

I borrowed a Wattmeter and set it all up, only to find that the motor cuts out at about 5/6 throttle

 

Of course, being a 360mAh 20C battery, it can only deliver 7.2A at most (and I wouldn't want to get that too close to that anyway!) so the ESC cuts out before full throttle due to voltage drop.

Anyway, I tried using a bigger battery, a Loong Max 500mAh 20C battery, which was fine, and I got the following results:

7.5A at WOT
7.13V at WOT
53 Watts.

The folding prop blades are 6"x3" Graupner on an MP Jet Spinner which has 40mm spacing between blade root pivots. This makes for an actually prop diameter of just under 7".

 

Fortunately I haven't started on the nose section yet, as it looks like I'll need to use a smaller spinner.

 

I'll probably need to get one of the Graupner spinners that only fit 2.3mm shafts and either turn down the motor shaft or drill out the spinner. Unfortunately I will need a lather for either and I don't have one.

 

Apparently other club members are mainly using Robbe 6x3.5 props which seem to be about as easy to find as rocking horse manure.

 

Hummm..... Any suggestions?