Alex Mini 1.5m mouldie glider build.

[chrispy]

 

Hi, to everyone who is interested in following my experiences with building my first mouldie.

 

I scouted round the suppliers and various forums to find a suitable one which had a 1.5m wingspan, was 2.4Ghz friendly and had a 4-servo wing. I finally chose the Alex Mini from Acemodels.co.uk.

 

It arrived well packed in a long plain cardboard box containing what you see in the photo. The wiring harness also came from Acemodels but was purchaseed seperately. 

 

 

Also included, but not in the picture, was 2 pages of instructions and pictures giving the basic start set-up values for the control surfaces.

Very impressed by the overall finish, especially on the wings and tail.

 

Has anyone else built one of these ? If so, how does it fly and what advice would you give me before starting?

 

 

[Tim Mackey]

Hi Chrispy and welcome to the forum - can you give us some more info on the model please - how much, etc.

Im interested

[chrispy]

Hi Timbo,

This model is imported from NAN models in Bulgaria by Acemodels. Price in UK is £229.25.

 

Wing span  1490mm

Fuselage Length 990mm

Wing Profile  RG15 mod

Wing Area 21.8dm2

Tail Profile HD801

 

See http://www.acemodel.co.uk/Slope/Alex-Mini-1-5m/prod_168.html

for more details.

>> 

[Former Member]

[This posting has been removed]

[chrispy]

You're right !  

 

I've flown alot of power and quite a few electric gliders.

 

See this video mounted on a model. Paste it into youtube and hopefully it will work:

 

http://www.youtube.com/watch?v=3RPk9_Rmv3M

 

 Our club field is in Cambridgeshire with no slopes within a 50 mile radius. So I'm going to have to travel to fly this model probably the nearest is Burrough Hill, Leicestershire of Ivinghoe Beacon, Bucks.  I intend to take on holiday - Peak District this year.

[Frank Skilbeck]

Chrispy, I bought a Mini Blade 2nd hand just over a year ago which looks pretty similar to your Alex Mini, here's my observations/thoughts

 

i) Let it fly, while me Blade will fly slowish, it feels very sluggish, but let it go and it really comes alive. Even if the lift drops off and you are tempted to hold in some up, don't, keep the speed up. The energy retention is great.

 

ii) It really needs the crow brakes for landing, otherwise it never stops.

 

iii) On my blade I have the Tx set up so I have separate flaps and ailerons in one flight phase and in a 2nd flight phase I've mixed the flaps in with the ailerons for faster roll response. Separate flaps and ailerons for landing (so flaps stay down) and mixed for general flight. Crow is on the throttle stick and the flap lever is set up like a flap trim to give slight negative flap for speed and slight positive flap for thermal.

 

Here's a piccy of my Blade doing what it does best.

 

 

 

 

[chrispy]

Thanks Frank for the advice on flying, Nice picture .

 

The Mini Blade was certainly one I considered.

 

I'll certainly take into consideration your set-up when I get round to programming my Tx.

[chrispy]

Looking in more detail at the components.

 

Fus weighs 95gms.
Access to the cockpit area is via a removable cover. 

Push rods are already fitted as thin wire rods in plastic tubing as can be seen above.

The fus  is very narrow, only 30mm wide where the servos will be mounted. Careful planning is going to be needed to get everything needed in this space.

 

 

Wings weigh 327gms. To me they feel very heavy for their size but that is probably because I'm use to handling balsa/foam wings. This is the first set of glass wings  I've handled.
Servo wells are already cut out. Good - that will save alot of hassle!

The black base in each well suggests to me the use of carbon fibre in the wing.Really impressed by the way the wings are made. There is minimum gap at the ends of the flaps and ailerons and the sealed hinges are superb. 

Tail weighs 31gms.

Fitted with a screw to the fus.

Again, a very nice piece of work. Looks like mounting of the ball connectors will  be a easy job.

 

My fingers are itching  to get going.

 

 

 

 

 

[Tom Satinet]

They fly well. I've seen them and the larger alex XL fly - they are good models.  The alex mini is pretty light in comparison to the mini blade.

 

I think that's a very good buy for the money.

 

 

[chrispy]

Do something easy to start .

 

Solder  threaded couplers to the tail end of the pushrods. These were not provided in the hardware pack and so had to raid my spares box .

 

 

The ball sockets (supplied) were then added.

 

Next step is to fix the ball connectors to the tail.

 

 

 

The ball connectors were too long and had to be shortened before being cyano-ed and screwed into the prepared mounts. The instruction leaflet says care is needed here to ensure the hole is not too tight as this can lead to splitting or snapping of the ball inside the mount.

 

 

[chrispy]

I've done a brief survey of forums to identify what servos have been used in models of similar size. I have no intention of using expensive servos and size is obviously going to be a limiting factor. Have decided to use HS65s in the fus and for ailerons. My experience with the MG version of these is that they have some 'slop' and therefore I've  bought the BB version from my local model shop.

These I find fit the wing but rise slightly above the surface at one end. The servo covers appear to fit over them OK.

 

For the flaps, metal gears are probably going to be essential if I have some landings with flaps down. Decided to try Vigor VS-12M which I've ordered from Hobby King. They are available in the UK but at signicant higher cost.

Spec for these is:

Operating voltage 4.8V DC - 6.0V DC.

Operating speed 0.14 sec/60 degrees at 4.8V

Output torque 1.5 Kgf.cm at 4.8V

Weight 8.0 g

Size 25.0 x 8.7 x 21.6 mm

 

These are very low profile and are completely hidden in the wing.

[chrispy]

Spent alot of time trying to decide the best way to configure the servos in the fus. It would be nice to have them side by side in order to save space but there is just no way I can get them to fit - they will have to be ' in line'. Therefore, made a servo tray in which I can also put the switch.

 

 

In planning the cockpit space it is necessary to consider the need to place a load of lead up front in the final stages in order to get the right c of g. The battery will also need to be placed in the nose area as far forward as possible. It seems to me that it makes sense to have the servos also as far forward as poss. which means the Rx will be positioned at the rear of the cockpit area.

 

The plan is to mount the servo tray on two strips of hardwood epoxied to the fus side so that it can be repostioned or removed for access purposes/

 

[Tom Satinet]

i think the biggest piece of advice I would give, is to fit a ballast tube, if you have not already fitted it. It will open up the range of the model a lot. 

 

 

[Peewhit]

Looks very nice Chrispy, and yes, get the heaviest things as far forward as possible but you do need to make sure that there is enough space for the lead.

 

Perhaps a dry run to check C of G (albeit approximately) before you start to epoxy in that nice servo/switch mounting tray?

[Peewhit]

ps have you flown a slope soarer before?

[chrispy]

This is the nearest that I've been slope soaring.

 

With a foamie when on holiday.

I think a mouldie is going to be a whole different kettle of fish.

 

[chrispy]

Hi Tom, glad you mentioned about a ballast tube. I did initially think about fitting one but having read in other forums what is involved in fitting one I put it at the back of my mind for two reasons:

1. because this is my first mouldie and it is enough of a challenge to get it assembled without adding extra complications and,

2. because with such infrequent opportunity to fly this model I don't think I would get the added benefits.

 

Hopefully, I will be able to build this one in such a way that if I change my mind I can add one later.

[chrispy]

My thoughts are turning to the wing and what needs to be done here.

 

The instruction sheet says. ' the pushrods for the ailerons and flaps should exit at the top of the wing. If you find this method too complicated you can modify the installation and run the pushrods parallel with the bottom of the wing and the control horns exiting the surfaces at the bottom but you may find that you will not have enough travel on the flaps for crow braking. You will also have to cut slots in the wing servo covers.'

 

Decisions, decisions, decisions !!!

[Tom Satinet]

In any sort of wind you would want to fly a model like that will ballast in all the time, to be honest.  It would pretty much be my #1 priority at this stage of the build (i.e before all the rest of the gear goes in the fuse).   Mouldies need ballast. Especially light ones like that.

 

As for the other issue. I would stick with bottom hinged, top driven surfaces.  It's not complicated really.  It sounds more hard work to change to bottom driven.  Top driven will given you a lot more flap movement which is good for crow brakes and if you go with horns underneath you will need to use very long horns (top driven horns include the thickness of the surface relative to the hinge line). 

[Tom Satinet]

i do realise though that if you have not worked with glass cloth (and don't have it + resin). making a tube does seem like hard work.

 

if you have access to any plumbing stuff 15mm copper fits almost perfectly inside 20mm overflow pipe (not sure that is appropriate to this model though).

 

anyway, I just don't like to see a model not reach it's full potential. it's a shame nan doesn't provide a tube. I'm sure most people would be happy to pay an extra fiver to get one. 

[Tim Mackey]

And the top horns will be better protected against "arrival" damage on the slope.

[chrispy]

Thanks Tom for your input on the ballast tube, I'll reconsider.

 

I'll have a look around and see if I can find something suitable (already made) I don't really want to mess around with resin and cloth. Maybe I can find something on the web.

 

 

[Tom Satinet]

it is a good idea to have one, but it is a bit of a hassle.  

[chrispy]

OK. I agree. Make the pushrods exit top of the wing.

 

This is the part which I am hesitant about doing - cutting into the lovely finish on the wing. Make one mistake and its going to be difficult to rectify.

 

What do they say? Measure twice, cut once?  I say measure four times, cut once!!

 

I've eyeballed top and bottom of wing with the servo temporarily fixed in position and marked the top surface where the exit hole is required. Covered this area with masking tape and then measured accurately several times before placing the marks on the tape.

 

 

Measure again and again and ..................

 

Now where's my mini-drill?

 

 

Edited By chrispy on 10/02/2010 09:23:26

[chrispy]

Did this in two parts. Started with the ailerons and then the flaps.

 

I used a router tool to cut the slots and had to remove the tape fairly soon after making the cuts because it it masked the edges which needed to be cleaned up. Most of the rear spar (balsa) was also removed at this stage.

 

Holes were drilled in the ailerons for the brass horns (supplied) and I spent alot of time deciding how these should be fitted to get the right geometry for then to work with the control rods.

 

Each horn needed shortening before fixing in position. Before gluing I put a clevis in the horn to ensure orientation was correct and then fixed it in postion with epoxy and microballons. The clevis was removed after the epoxy had set.

Care was needed at this stage to prevent epoxy running into the hinge area.

 

It has ended up like this:

 

 

The flaps were done in a similar way but the horns were raked further forward.

 

For the flaps to work it was necessary to remove part of the wiper immediately under the clevis. I found that the material the wipers are made from is very brittle and some it broke off which can be seen in this photo

 

I realize that the horns may be too high on the wing surface and perhaps should be raked even further forward so that the whole mechanism is almost hidden  in the wing. You learn by experience! 

I plan to wrap the servos in masking tape or heat shrink tubing, if I have some which fits, and epoxy them in the wing. Any comments?  

 

 

 

Edited By chrispy on 11/02/2010 09:09:52