Mini Tyro

[David Ashby - Moderator]

We met up with Andrew Boddington (David's son of course) yesterday to shoot his Mini Tyro. It flew well, Andrew's a really nice guy and we had a great day. We took some video too that'll be available on our YouTube channel soon.

 

It'll be the free plan in the upcoming Nov issue (along with the Cygnet wing) and essentially Andrew has made it a three-channel model (rudder, elevator, throttle) with a Mills .7 in the nose although an electric conversion should be pretty easy. A CNC parts pack will be available although it's a relatively simple model construction wise - constant cord wing etc.

 

 

 

 

 

[David Ashby - Moderator]

Another pic...

 

[Rob]

Looks great , could be a contender for the vintage mass build. Looking forward to november issue but still havnt finished the summer special yet...

[Mark B]

Hey, thought the mag ed might be interested to know i built a mini tyro a few years back, had ail, ele, and throttle. flew well. Resurected half a year ago with new foam wing veneered in brown paper. Same controls, flys for about half an hour on a 1000mah battery. Yes its electric. No landing gear though as i fly from parks used for rugby and the like.

Edited By Mark B on 18/10/2011 06:49:33

Edited By David Ashby - RCME Administrator on 18/10/2011 08:03:15

[Mark B]

I just noted that there's no landing gear on the photographed model either. The tailplane is quite large which makes the stall charateristics very forgiving, but the fin is slightly too small if ailerons with no differential are fitted. Shouldn't make a difference if there is rudder though.

 

Another of DB's designs that i built was a Double up. Biplane/monoplane interchangeable thing. Mine didnt fly very well, suspected lack of tailplane area. Has anyone else built one?

[Robin Kearney]

There are countless DB designs I've fancied over the years, but I've never quite got round to building one.

Except this one! I've got the fuselage sides cut out and after tomorrows trip to the local model shop I'll have enough balsa.

Still wondering what to power it with, am quite tempted by a little PAW after the success I had resurrecting my 1.5cc version in the C/L Phantom.

Our second child is due first week in December so let's see how close I can get before that hard stop

r.

[kc]

Anyone care to suggest a suitable electric motor/ ESC/ Lipo for this model? It weighs 13 ounces according to the RCME article ( can that be correct? )

 

Very readable article - fully up to Boddo senior standards! What about an updated Mannock next for a free plan?    ( for the newcomers a Mannock is an SE5 look alike )

Edited By kc on 24/10/2011 16:36:31

[Tim Mackey]

How about THIS

[kc]

Would it need as much as 125 watts for a 13 ounce model (well maybe 1 pound with the battery) of vintage / trainer style ??

[Steve Hargreaves - Moderator]

You don't need very much power for a Mini Tyro.....I have an IC version with a 1cc diesel in it & it flys very nicely but quite quickly. I wouldn't like to fly it with rudder only....!!!

 

I also built another fuselage which I fitted with an outrunner...a Vortex something or other I think it is supplied from a 1300 3S Lipo. I first flew it with about 100watts for a 16oz A-U-W & it was too much....the torque of the motor wanted to roll it every time you opened the throttle.....I propped down to about 50watts & it flys very well at this level which makes me wonder does a 1cc diesel really only produce 50watts...

 

Tims suggestion would be great but don't prop for max power.....a 2S set up would probably work nicely too.....with a nice big prop for wafting around the evening sky....

 

My IC version...

 

[Tim Mackey]

Exactly, either just use a 2s, or prop down, and use throttle management.

The power figures given for motors are the peak, and running them at well beow that is good for 'em.

This is a pretty small and cheap combo setup - and you did sound a little dubious about the AUW kc

[kc]

Thanks Steve & Tim.

I consider myself a light builder but as I normally build 4 pound .40 size models I thought 13 ounces must be a misprint! I would fit an u/c and aim for 1 pound for an electric version.

 

All depends on whether the Mini Tyro is selected as the Mass Build design or not.

 

[Mark B]

hey, i own and fly an electric version, 14 ounces all up with battery.

 

1000mah zippy 2 cell battery

GWS 2205-15T motor

GWS 15A ESC

 

Mine has ailerons, elevator, throttle, no rudder.

Almost 1:1 power to weight ratio with this set up. Cheap too, i think about $30 for the motor and ESC combo and $5 for the battery through hobbyking. NZ prices.

 

Undercarraige is no good unless you have a really smooth runway / tarmac. the wheels are just too small. saves weight too.

[Mark B]

Sorry, 8x4 e prop as well.

[David Ashby - Moderator]

I've double checked the copy and the weight is correct although I guess the i.c. version would be a little lighter than a leccy model.....

 

 

 

[Mark B]

The original version i built used the above setup with a built up aileron wing, which basically followed the plan. If i remember correctly it gave 10 - 15 minutes of flight time. The next time i referbished it, the motor i originally had was in another model, so a cheap motor was bought from hobbyking for it. It was a Turnigy Aerodrive C2826-1650 with a GWS EP-8040 propeller (bright orange prop as standard, very easy to see in the air and on the ground).

The old wing was my second attempt at built up wings done as a teach myself how to build, (ie not too hot) so my refurbished version got a foam wing, the same section and wing chord, but at 40 inch span, with balsa tips, and veneered in brown paper. Neither wing had dihedral. The fuselage was fine so remained the same other than the motor change. Latest flight time was 20 - 30 minutes, 20 with full aero's going on all the time, 30 while cruising on half throttle with lots of low level circuits ie less than 1m altitude.

[Tim Mackey]

Posted by David Ashby - RCME Admin on 25/10/2011 08:07:11:

I've double checked the copy and the weight is correct although I guess the i.c. version would be a little lighter than a leccy model.....

 

 

 

 

Really?

I reckon if you go small to medium capacity 2s with one of those suggested small bell outrunners, there wouldnt be much in it - I seem to recall diesels being quite heavy little things for their size?

[kc]

Tim, Is your suggested BRC motor & ESC still the choice? i.e. is it similar spec to those other people used? This is the trouble with us oily hands thinking about electric........equivalence of different makes especially when items go out of stock or get the name changed by a different importer.

 

Battery. Is a 500 or a 1000mah 2S Lipo suitable for above motor? 5 dollars ( ? NZ ) for a battery! They seem to be about 10 pounds in UK.

 

It seems that the weight must be about right as others here achieved similar weights. Perhaps they used 'contest grade' balsa not the usual model shop stuff. Lightweight covering is normally the key to light models though.

Edited By kc on 25/10/2011 11:08:36

[Tim Mackey]

Oh it was just quick suggestion really kc - there are LOADS of similar low power setups around. Any small 80 - 150 watt outrunner of around 1000 -1500 kv or so will be fine.

 

Heres another example from the big fish.

 

I'd go for the 1000m/a battery otherwsie youre flight times will be pretty short!

Something around 1500ma would probably be better, but the 1000 ma will work.

You could always parallel them up together, and then youd have a 2s @1500 m/a

 

Edited By Tim Mackey on 25/10/2011 13:37:16

[kc]

 

Noted, Tim.

 

The RCME Mini Tyro article is extremely good for anybody just starting building. However one of the 'essential' items specified is glass headed pins. There may be good glass ones but I had ones which shatter under thumb pressure and the pin penetrates your thumb! Proper T pins as sold by SLEC are much safer. 'Map' pins with plastic head also have their uses in modelling.

Edited By kc on 25/10/2011 18:57:29

[Mark B]

Trust me, 1000mah is fine. $5 NZ is only through hobbyking. Otherwise like you i would be paying $30 per battery / 10 pound. Using a 1500mah battery would increase the weight too much and therefore use more power to remain airbourne and therefore not have any better duration or performance. I'm flying a mini tyro built from the original 1970's plan, no competition balsa in it, just cheap stuff, and with standard 65g per metre solarfilm, and 9g servos. The article in the latest mag sais he modified the fuselage underside to 1/16 balsa and 1/16 ply. this is not necessasary as i have 1/8 cross grain med balsa and it has survived its 5 - 6 year life flying from parks and paddocks so far without injury. My model has a hatch in front of the wing for battery and ESC access and the original removable tailplane, very useful for transport in a suitcase. Although my tailplane is a 1/8 built up flat structure to save weight and speed up the building process.

 

see above posts for electric set up and flight duration.

 

i'll try and get a picture or two on my profile of the model, i mainly fly right on dusk so don't get many chances for photo's.

[Mark B]

Static photo's are now in albums, i'll try to get some flying shots soon.

[kc]

There is some error in this months article.......elev movement is shown as .4 inch ( 7mm ) obviously an error. Which is right?

Also is the rudder movemnt only .35inch ( 9mm ) each way. Doesn't seem much. Is it correct?

 

Of course these are always just starting points and need to be adjusted for personal flying style but it's much better to know what works well enough so you can avoid a prang or a heart attack on the first flight. 

 

What are you using for elev & rudder Mark B ? ( assuming you used standard size rudder & dihedral )

Edited By kc on 26/10/2011 11:10:02

[Mark B]

No rudder or dihedral on mine. I dont have much cash as i dont work so opted for just 3 channel with aileron, elevator and throttle via an ESC. The lack of dihedral has no adverse effect on handling, full span strip ailerons help with the manueverability i require to fly from small parks with trees, lighting poles, and rugby posts on them.

A rudder is easily fitted, but dont expect the mini tyro to aerobat too well. Mine will roll, loop, chandel, does a passable stall turn using motor torque, and can just hold inverted at full throttle.

 

The elevator has about 1/2 inch travel each way, but my elevator is bigger than shown on the plan, i dont know what the rudder should be, but would guess about 10mm each way.

 

Note: The fin is quite small - therefore the rudder is also very small. Beware of the torque effect of a large prop on a small plane. I run an 8x4 prop, whereas the original version with a dart diesel had a 6x4. I dought a rudder, elevator version would hold the model straight on climbout.

 

See my pics for rough sizes of control surfaces.

[kc]

I think we would like to see a correction for the misprint & know what the elevator movement etc was for the RCME test model.