Indoor season starts here in a couple of weeks time. I want to get more people involved so I set out to make an affordable trainer. The target was to keep the total cost under DKK 400 (app USD 60). Whilst it is just about possible to buy a RTF model for that amount, once you add shipping and Customs fees and 25% VAT on top of goods and shipping it becomes a fair bit of money. However, if the value is below DKK 300 there are no additional charges to pay. For R/C equipment I have selected the excellent HiSky RX brick and TX from their Buzz micro model. Brick and TX is DKK 250. I also use the 150mAh cell from the Buzz and a cheap USB charger. Motor is a 8.5mm coreless motor with a Walkera Ladybird prop. I plan to build another of the same model but will use the geared motor from the Buzz. I just didn't have any suitable props for the prototype. They have since arrived. The geared motor is a bit lighter than the 8.5mm direct drive motor and draws less current for a similar amount of thrust.

The model has an undercambered wing made from 3mm Depron Aero. Fuselage has a skeletonized 6mm core and is clad with 3mm sheet. A plain 6mm fuselage might suffice but I like the slightly chunkier look and it will probably stand up to novice pilot abuse better. AUW is just under 25 grams. Wingspan is 44cm. I named it (very unimaginatively) "Skubber 40". "Skubber" is Danish for "pusher" and 40 was the span in centimeters on the first draft. I cut the parts on my laser but they are not too hard to cut by hand. Total build time for me was a leisurely 2 hours.

This afternoon we had a rare moment of sunshine and hardly any wind so I got a chance to maiden the model. It is very easy to fly and putters along on 1/4 throttle. It glides surprisingly well for such a small model.

For now, here is a picture and an outline screenshot. Plan to follow.

EDIT: Plan attached. Full and tiled for A4 paper

Brilliant!

Very well thought out Michael.

Many thanks.

I have attached the plans to the first post. The little wedge in the skeletonized part of the fuselage is for the motor. The motor is simply stuck onto the wedge with UHU Por and it is then glued to the top of the wing.

It will cruise at the lowest possible throttle setting on the Hisky brick so I think a 7mm direct drive motor would suffice, especially if the fuselage is just made from 6mm Depron. I'm sure it will be great with the Hisky geared motor and a 75mm prop. I use a quad prop meant for CW rotation as a pusher. That way the motor still spins CW as it is made for. I'm a big fan of the Hisky geared motor as it is inexpensive and works well. With the stock prop it pulls app. 1A on a freshly charged cell and gives 30grams thrust. One important point though: The bushes MUST be oiled or they will seize up and wreck the motor. A tiny drop of oil is all that is needed.

The main reason for making it a pusher is to avoid beginners wrecking motor and prop. However I also had indoor FPV flying in mind and I will build one that will carry the amazing little FC798T camera/VTX combo which only weighs 4.5grams.

Below are some equipment links. I'm not affiliated with Banggood but it is my preferred source of parts as their have low shipping rates to Faroe Islands.


Motor/gearbox

RX Brick

Transmitter

Props for pusher config with geared motor

Lipo

I will take some pictures when I build the next one. It's fairly easy to build. I can probably assemble the whole airframe in around 30 minutes.

Everyone who turns up at our indoor flying session is offered the opportunity to fly. When we started, one of my MazZip's was the "victim" and actually survived most of the season. However it takes longer to build so I needed something simple for this season. I plan to be building quite a few of these. There are a couple of guys who are already interested in joining but they don't fancy building the model themselves. Others are also interested in building but they don't want to wait a month for equipment to arrive. Therefore I have built up quite a stock of parts which I pass on at cost.

Very cool trainer!

Thanks, Dave-

A very nice easy design.
Just a brilliant idea stocking up on some cheap parts as a service to your fellow pilots. Iv done it on lipos but might go full out like You too.

/Ulf

Originally Posted by methuso

A very nice easy design.
Just a brilliant idea stocking up on some cheap parts as a service to your fellow pilots. Iv done it on lipos but might go full out like You too.

/Ulf

Thanks. It's about self preservation really. We pay to use the gym so if more participate the cost per pilot is lower.

Not everyone is confident ordering from the likes of Banggood or may have language issues so I do a lot of purchasing for fellow modellers.

I find it is a lot easier to get people interested in the hobby if they can get their hands on a working model straight away.

Exactly. It might be hard to resist a cheap model that some evil guy is waving at your face

Hello Michael, glad to see you online again. Looks like you are the Santa Claus of the Faroe Islands I have yet to order from Banggood because I have been reluctant to give them my CCard info. You seem to be comfortable dealing with them so I guess I will give them a try. Unfortunately that Buzz rx does not seem to be compatible with any of the usual protocols. Dave

I have the belly but not the beard to be Santa.

I have used Banggood for a number of years and use Paypal to pay. No issues.

I have both Devo 7E and 10 with extra modules installed so they can work with the Hisky RX. For a basic TX the Hisky one is pretty good and only around USD25. You can also get a module from Hisky that plugs into other transmitters.

We had our first indoor session this afternoon. Sadly only 3 people turned up so I'm DKK 900 out of pocket for rent of the venue. Still had lots of fun though.

The Skubber 40 flies well and will definitely be suitable for beginners. I flew the model with the geared motor with FPV which was a first for me. Apart from slight nausea, it was great fun. Without the camera we tried to time flight duration if flying at cruise speed. After 38 minutes I had to land as it was time to pack up but there was still charge left in the cell. This was the cheap 200mAh cell that you can buy for the V911 heli's. The cheap Hisky transmitter is very nice, it has better joysticks than many of the toy RTF models.

Just charged the cell and I put 168mAh back into it. If flown to LVC they will take a 205mAh charge. This tells me that I could probably have flown close to 45 minutes. Pretty impressive I think. I must have got the undercamber on the wing just right, decent lift but not too much drag.

finished the scubber yesterday! no depron here in usa, so i used 5mm epp for the fuse. d.t. foam( adams) paper off both sides and meat tray foam for stab and elevator. wf949 brick, hubsan replacement motor with 3020 prop.
ended up at 27 grms and using 8 grm. battery is rtf at 35 grms. as epilot said it flys with low, low throttle. great plans and love the model
hats off to epilot u need to build this one !!!!

jerbear

here is pic

Looks like your motor has no upthrust. Here is a pic of mine.

Do you mount the lipo on the same side as the TX? I recommend mounting it on the other side to provide some counterbalance.

Mine with the 8.5mm motor and a 150mAh cell weight 26 grams.