Chris Walby

Hi, I am thinking of building a quick model (not 3D!) based around a SU 37 shape with either a pull or pusher depending where the C of G ends up from Depron So for fast flying what's the minimum in need in control surfaces to get it to do most of the usual moves. Canards with one of two servos as elevators or elevrons Rear elevators or use these as elevrons Rudder? Wing TE Ailerons?     Edited By Chris Walby on 02/11/2016 14:08:17

Tom, Sorry to hear about the diabetes, but it might be worth searching out the motor cycle web sites as some do all kinds of heated under layers and most likely 12V rated, so one Lipo pack in the plane and the other heating your feet!

If you really want to be sure, either with the prop off or make sure you are behind it, turn the TX on, then battery in the plane and on. Let it bind and settle down. With the stabilisation switched on (if your can turn it off/on) hold the plane and yaw it right you should notice the rudder moves in the opposite direction to counter you movement. Then nose the plane down and you should see the RX put in up elevator and lastly roll it one way and again the RX should drive the ailerons to correct your movement. I have a AR636 and have been playing around with the different settings so like to have the option of turning off the stabilisation inflight in case I have overdone something. Lastly if I remember rightly the AS3X needs a few seconds (5 ish) of straight and level flight to sort its self out, it does this once the throttle is up by 40%. PS... Make sure the plane is well mechanically trimmed up as the AS3X does not like massive levels of TX trim put in. Hope that helps

There will be better answers than mine as I don't know the size/weight, but I would start with measuring the existing CofG and replace parts like for like based on weight. Weight the existing battery, speed controller and motor and take a note of the prop size. Then aim to replace like for like within reason! If the new kit is too light I would suspect you will be well under powered, equally not much point having a ballistic rocket that has loads of lead to get the CofG and glides like a brick! From a review on the web Wingspan 32.5 inches Fuselage 31.2 inches Weight 17 ounces Prop stock Motor BL400 Battery 11.1v 2100mAh Watts 178 Amps 20

Following the build very closely and it looks great.....dumb question? What is the brown paper method?

If you have the Zagi 400 already not an option, however 4-Max do their own version called the Yeti with an optional electric pack and George was very helpful regarding set up. I got mine to fly when the conditions are not suitable to fly anything else or I am not prepared to damage a balsa ARTF ! Great fun and probably almost indestructible as its foam & packing tape! Will fly very slow all the way up too quite quick and you can make it as visible as you want (good for those winter grey skies)! Only down side is that it has no rudder so no stick practice there, but goes in the car so set up time is minimal (just safety check and fly!).

....so where does it return to.. the flight line where it mows me over (I'll have enough trouble flying the Vulcan as it is!) or the pits via the fence....How about I retrieve the dolly and someone with greater experience with maiden flights has the sticks... Any takers (when are you next up at the field?)

Steve, I have a Yeti delta wing which looks much the same as you FX-61 in size/power/weight and all I do with that is hand launch it. I think a dolly will be more trouble than its worth to be honest I was advised with two techniques for launching firstly the hold the centre and above head throw with motor off, as it glides toward the ground power up and a bit of up elevator or discus style (hold it by the end of the wing with wing in front or your body at about 45 degrees. Then throw into wind away from yourself. I prefer the second technique as I put throttle hold on, give it full throttle and throw it with my left hand (I am right handed) which leaves my right hand holding the TX with my thumb on the elevator/aileron stick and my second finger on the throttle hold switch (on my TX its mix/hold switch is top right). So throttle hold, throttle to full power, ready to throw, take throttle hold off and once its up to full speed, throw firmly into wind (with right thumb of TX stick) and away it should go! The only other thing to mention is the harder I throw mine the worse the launch (within reason) because what I tend to do is introduce rotation into the throw. The Yeti has no rudder or centre stab so if I introduce yaw I only have elevrons to correct it with.

I have read the article with interest, not sure I am prepared to stretch out a bungee with 30kg of pull (that is a lot of stored energy!) and let go of a delta wing model for its maiden with just elevrons and flaps....Might need two bin liners for that! Back to the dolly I think

Thanks to those that have posted and after a bit of web searching a design is being formulated, Two front wheels, with one trailing (possibly steering, but will try it without first), it will be quite wide for stability and to miss the pusher props which are 12 inch apart compared to the 6 ft wingspan.

Hi, It looks like I will need a launch dolly due to U/C position and pusher props on a 6Kg Vulcan (it can land on its U/C when it comes back down). The runway is grass, a bit bumpy and quite short! Does anyone have any photos/drawings of a launch dolly that would be suitable as its a bit pointless reinventing the wheel so to speak. And is there any benefit in say powering the dolly to help it on its way either bungee or self powered? Many thanks

Hi, For me its not the wind speed that's the issue, but the gusts so if its blowing a constant 20 mph down the runway it makes the down wind leg fast and landing easy. However it could be 10 mph gusting 25 mph cross wind and almost impossible to land a high wing foamy in the cross wind. So to help me I use a "to fly factor" which is the gust speed squared, divided by the average wind speed off the met office web site! That way it could be 20 mph average, gusting 25 (=31.5) which IMHO is more flyable than 15 average gusting 25 (=41.7). I just plug the numbers into a spread sheet for the week ahead and see which are the best days to fly! Normal cut off is if the factor is greater than 40, I'll give it a miss unless I get the delta wing out (Yeti) and do some stick wiggling! PS the spread sheets gives some interesting historical data, like only a 40% chance of flyable conditions based on the factor 40 threshold for this year. The bottom line is..."is it safe to fly" after that are you prepared to do the long walk with the bin liner!

A couple questions for the electric version build. There is a covered yellow panel & U shaped piece of wood that does not appear in the instructions! Does the U shaped wood just get attached directly on to the fuselage (remove covering before gluing) as it does not seem to fit anywhere else! It will just look a bit odd as its got no covering on it. I have a bit of spare covering or paint it, jus seems odd for such a well engineered kit Second question, the elevator control rod rubs against the fuselage to a point I can't get the wire in the outer hole of the servo arm. Is it best to trim the fuselage or bent the control arm wire?

I was going to say how about a three blade prop, if you can't get a 4 blader

Thanks to all who have replied, I'll digest your advice....To answer Ray, yes the watt meter has been employed, but I am not seeing much as its a 320KV 1600W 80A motor on 5S lipo pulling 9A & 415W on a 2 bladed 16 x 10 at 1.7kg thrust...and there is my dilemma...should have got a 580KV motor! I have a plan...3 blades and then failing that 6S lipo. I was interested to see comments regarding the low/mid air speed effect...

Some insight or opinion would be warmly welcomed on the question of propeller performance and its effect on an electric set up (assuming motor & ESC are easily capable of driving either of props). Is there a difference in low, medium and high air speed performance between say either a 8 (dia) x 10 (pitch) or a 10 (dia) x 8 (pitch) beside the theoretical higher speed of the former? Second question, what effect does running high pitch props do for low air speed (landings) performance on throttle response at the TX stick, if anything with something more extreme like 7 x 10 pitch?

I would have thought grass will have more drag so once its down it will stay down + grass is a bit softer than solid tarmac in case it was a harder landing that expected.

Hi, Just read your build and watched the flights and it looks really great. Do you know what the all up flight weight was? And have you had any interest in supplying its as a kit? PS where is your shop?