Simon Chaddock

The question is why have these suppliers decided to quite. If it is a proprietors choice then no issue but if it is due to a decline in the market then the long term future of IC supply could be rather more serious unless so new suppliers enter the market. Unless new engines enter the market the second hand ones will eventually wear out beyond economic repair. Surely the world wide adoption of electric must have an impact on the size of the model aero engine market.

John I certainly hope to be there but some medical issues may get in the way. It comes to us all!

Sorry no flight pictures as I was the only person at the field but I flew the FX707 Albatross RC power conversion today early (9am) before any gusts appeared from a strong sun and cold air. With the flaps set at 15 degrees it just floats along. With just a 1500mAh 2s it flew for 35 minutes 57 seconds power on. It still had some power but I didn't want to risk damaging the battery As it turned out the cells were still sowing 3.73 and 3.74 at rest so a few more minutes should be possible.

Well done! Those nacelles are very neat. I like the temporary(?) struts to hold the planking in place.

Welcome to the forum. You might be surprised just how many have done exactly the same thing, myself included, perhaps it helps explain the average age! As you have found things have moved on quite a bit not least with the advent of FPV flying and quads all loaded with amazing electronics. The other significant change is the advent of electric power although from your background I would imagine IC will be your primary interest. Finally remember the environment has also changed with CAA registration required, including a theory test, for a pilot to fly any RC plane that weighs over 250g. Do you intend to join a club?

A small degree of aileron droop will reduce the stalling speed but the question is by how much and would you be able to make use of it. How close to the stalling speed on approach are you able to fly comfortably? Is your landing problem a high approach speed (safety in mind) with a resulting high touch down speed and long landing run? The Learjet is not a slow flyer and the full size has big flaps that descend to a maximum of 40 degrees for a reason. It would risk loosing roll control to droop the full span ailerons by such an amount. Rather than full span ailerons you may do better to copy the full size configuration but it would of course require some modifications.

clive You may get lucky but I fear you may have to do a bit of DIY modelling. Find a 3 view of a mk1 Spitfire on the internet. You may have to blow it up to the correct size You will also need some balsa wood and then simply make a fin. If you ever fly it you are most likely to have to do the same sort of thing sooner or later as repairs!

I mentioned motor cooling. In your glider the motor is completely buried in the fuselage and sitting behind a close fitting spinner so there is very little airflow through to the motor. Brushless motors are efficient but at least 10% of the input electrical energy comes out as heat. In addition a brushless motor is very compact so it needs a positive airflow to effectively carry the heat away, Just a heads up.

Mark The required Watts/lb depends very much on how you want to fly your glider. You are quite right about the power a glider might require if you just want to cruise about under power for duration but for many the power is set up to give a rapid climb to altitude and then let the glider do its gliding. Electric is pretty good at doing this delivering high power for a limited time (tens of seconds) and then giving the battery a rest and let the motor cool down. One advantage of electric is it throttles efficiently so with a suitable setup you can do both in the same flight. Just for info In a brushless motor the full amps is delivered through each pair of the wires in turn. The unused wire is used for voltage measurement so the speed controller knows when to select the next pair. At 6000 rpm it will be doing this 100 times a second. The wonders of micro electronics! The only way to measure the amps effectively is what the battery is delivering.

I just Googled "DH Venom 3 view" and hunted through what it came up with! There is a build description in the "Own Design Project Blogs" section. It is on the second page under "A bigger DH Venom". It is no q "blow by blow" account but it does show the stages of the construction. Probably the most important part is not foam at all but the printed duct work for the EDF as when assembled it is used a "spine" so the fuselage can be built around it. I hope this helps.

Sorry no plan. It was scratch built from a small internet 3 view & tile printed to the required size. In fact this one! I rather liked the colour scheme used by the Swiss Air Force aerobatic team.

No They are likely selling "new" XPS sheet that is made by the Depron company. It does not have the original surface "skin" so is similar to other 3mm XPS sheet but maybe a bit better quality and price! I was told the original Depron was too expensive to make. Last year I collected a couple of the "new" Depron sheets (It even "Depron" printed on it!) from Steve Webb's shop before it closed down. Indeed this was made from it

Insulation! It will be a bit cold in winter. A big sheet metal door and no roof insulation.

shepeiro Looking good. Still find it hard to believe it will come out to sub 60g. I would not worry about the extra resistance due to extending the battery to Rx wire. It is not as if it will be carrying a huge current. It is normally poor contact in connectors than generate electrical resistance.

Basil Just be aware that to obtain the correct operation of the V tail you may have to "reverse" one or both servos using the Tx servo reverse function or even swap the servo plugs over on the Rx before you get everything moving in the correct sense but then you may be lucky and everything works correctly first time.

It was probably more likely to be delivered using a plane. At least it would have to be handled again when it arrived back in the UK rather than stuck in the "lost" pile at Heathrow.

Just remember that original Depron is no longer made. It was XPS sheet but was squeezed in a mould during the foaming process so it had a slightly denser skin on the top and bottom surface. This meant it had a smooth almost shiny surface and was more rigid than normal XPS foam sheet. It also had a significantly higher tensile strength almost equivalent to a soft balsa.

Albert It a 3A and reducing charge rate gets a 3350mAh LiPO full in 35 minutes then you are starting with quite a charge already in the battery, maybe as much as 65%. Nothing wrong doing that. It does avoids the possibility of an over discharge flight!

Jolly Roger The question with a slightly over discharged LiPo is not that it wont recover the nominal voltage but how much of the cell's chemistry has been damaged? Such damage usually takes the form of a reduced capacity. The damage issue becomes more severe if one cell has been effected more than the others. If the LiPo is then used that weak cell will reach a "damage" discharge level before the others and thus likely to be damaged further. There is the real possibility of a LiPo fire if the discharge of the weak cell(s) is taken too far. The usable capacity of a LiPo must be considered that of its weakest cell. With a damaged LiPo the problem is knowing what the reduced capacity is and acting accordingly. With LiPo it pays to keep flight durations conservative.

An under cambered section will create more lift so it will be able to fly a bit slower but if stalled the effect is likely to be bit more severe with a pronounced nose drop. Any small variation between the wings will mean a severe wing drop and the beginnings of a spin. How severe these tendencies might be will depend on the wing section and the degree of under camber. Some WW1 types with a thin section and under camber were deemed to be unrecoverable from a spin although the relatively sharp leading edge was probably the biggest cause. When Fokker introduced thick wing sections but that still had slight under camber the propensity to spin after a stall was virtually eliminated. A typical WW1 wing section. Fokker Triplane wing section. There is little wrong with the good old Clark Y section which is flat bottomed over the majority of its underside so can be built on a flat board.. I hope this helps.

Is it a wheel?

My humble 4 button IMAx certainly starts of a balance charge with the set charge rate. It gradually drops the charge rate and starts "balancing" (it appears to cycle around the cells) when at about 4V per cell. I too always balance charge. As towards the end of a balance charge the charger is using the balance plug to measure tiny voltage differences any slight contact resistance variation in the plug contacts can upset the end of the balance charge. Sometimes just a "jiggle" of the balance plug can result in a really slow balance charge suddenly being completed. 😄

Jonathan Changing the pins on a balance lead plug is tricky. Nothing like as simple as a servo plug.😒 I have solder equipment so my solution is fit a complete new plug and solder the old and new wires together covering the joints with shrink wrap. Do be careful you do not dislodge any wire from the LiPo itself. The cell tags are aluminium so unless there is some ordinary solder still visible you wont be able to solder anything back on..

Really very nice. About the only comment I could make is with the diagonal wing bracing strut. As you have them positioned under load they will put a bending force on to the vertical struts. Note on the full size the diagonal strut goes all the way to end of the vertical struts so no bending moment is created. I am sure it will be fine. Just a "picky" observation. The fuselage struts follow the full size so are no problem.

Nice idea but a structure capable of withstanding the forces as the foam expands would be very heavy indeed.