Arrows T28

Has anyone had/flown one of these models? Nearly finished installing the radio and setting up the throws etc. My main query is the CG position. In the instruction leaflet it suggests 45 - 50 mm from what looks like the front of the wing moulding which is not far behind the leading edge of the wing, and obviously is very tail heavy. There is a fillet from this moulding edge back to the wing which is from memory approx 20 mm. The root chord of the wing is 210mm. I have balance at approx 25% which seems right and puts the CG about 0.5 inches in front of the undercarriage main wheels (trike undercarriage) .

Any info would be welcome. Thanks in advance.

Sorry about the mix of imperial / metirc measurements.

JOhn

Edited By John Tee on 02/12/2019 23:09:19

Edited By John Tee on 02/12/2019 23:10:49

Have not got the Arrows T28 John

But have flown this size and larger.

In general, the T28 is an ideal flyer in model form

C of G on a trike is always in front of the main wheels in order to rotate at take off too

Just in front of the main wheels looks a good start point then adjust after further flights

This livery is spectacular

R C Groups I’m sure have a thread on this plane ! Colin

Thanks for the replies, been out all morning so not seen them. Looks like I was close with my estimate. Seem to have lost the program I had for CG calculations and the one I found on line was a bit too complicated.

I will have a look on RC Groups site to see what others think.

John

deleted due to double post

Edited By John Tee on 03/12/2019 14:35:56

John ! I've got the Bearcat and that needs lead right up front . It flies beautifully like that but take off and landings need short ,dry grass ! With flaps deployed it descends like an elevator , but always tip stalls a foot from the ground ! I roll it on flapless. Colin

Colin, Thre problem with the T28 is there is no room in the battery bay without surgery to put any ballast. On my Hellcat the cowl is held on with magnets and I got my ballast inside the cowl, but the T28 appears to be glued on. I haven't really tried to remove it yet but won't force it.

The video on RCgroups seem to show it flying very nicely, so looking for some decent weather to fly it. Access to our strip is difficult when wet and it is a fair walk with all the bits if we have to park elsewhere (3 fields off the road).

John

another double post, sorry,

Edited By John Tee on 03/12/2019 15:58:02

I also have an Arrows T28 (John Tee will know this because we are in the same club) and I thought it might be useful to outline my experiences. Firstly, I should say that this is my first war bird so pilot error is undoubtedly significant. However, there are shortcomings with this model that concern me. The first is the CG. I worked mine out from scratch because the instructions were inaccurate. I finally got the model into the air but damaged the nose wheel gear on the grass and had to uprate and replace that. Finally, and most significant I think is that my aircraft seems to be way overweight. Arrows state that the flying weight should be 1135g. I was, initially, flying it with a 3200mah battery to help with the cg but the model weighed in at 1500g with that. The best I can manage with a 2200mah battery and significant surgery to reduce weight is 1380g. That's an improvement but I think it is still heavy and I am sure that landings will continue to be interesting. I would have to say that I am disappointed with this model. Anyone else got any views.

Hi Graham, Have now replaced my noseleg wth the original but not yet flown. Will have to recheck the control movements as mine was way too sensitive but the balance seemed close to correct. Didn't weigh mine, will have to give that a go.

John

Just looked at the date of my original post. November last year. Still only had two flights with T28. Had to wait 2 months for a replacement nose wheel (seems a weak point) as I broke the drive screw in the retract landing short and ending up in the longer grass with the U/C down. Field not too accessible now with all the rain. Where has 2020 gone?

John

Graham, weighed my T28 yesterday. weight minus battery 1200 grammes, with 4s battery 1500 +/- a gramme or two. On my only two flights so far didn't seem too heavy. Very lively take off

John

Hi John,

I would say that your T28 is about the same weight as mine. Interesting that you fitted a 4S. One feature of mine is that it struggles into the air and then has to be flown above 75% throttle. Landing is tense. If the speed falls off a nasty stall can ensue.

Maybe 4S is the way forward?