MAD Dave

Initially I had a 27MHz set which was powered by a 9v dry battery for the Tx and 4.8v 500mAh nickel cadmiums for the Rx. I converted the Tx to 9.6v 500mAh NiCads which worked fine. All the rechargeables were the earlier round button cell DEAC's manufactured in Crewkerne, later rebranded as Saft; German for "Juice" I believe. My later 35MHz set was supplied with 2x4 "AA" (mAH not known) NiCads for the TX making ~9.6v and a similar 4-pack for the Rx, ~4.8v. I still use a couple of my original Fleet servos on a smaller aircraft model, they work fine. I never had a problem with my Fleet hardware, why it was given the flying field reference as "DodgyFleet" as opposed to the company "DigiFleet" I do not know; worked for me! Good luck Richard!

Purchasing a kit is fine, but f you really want the "I built that" satisfaction fix - buy a plan!!!

I'm with you Peter, there is only one type of solder!

Thank you everybody for your recommendations, looks like consensus is ~60W minimum; correct me if you disagree though please.

I am having to change my ESC connector to be compatible with the purchased LiPo's. It's an 80 Amp ESC so has pretty heavy supply cables that are acting as very efficient heat sinks! My current soldering iron is struggling and I am not happy with the ~dry joints it is producing. So, to attach 5.5mm barrel connectors to these cables, what wattage would members recommend please? Anyone have any favourite irons? A Maplin unit would be preferable, I could then collect it tomorrow from the local outlet and get on with my build........

Gave my "electrified" Seagull Sparrowhawk an airing at the weekend, fifth flight; very pleased with it!

Piers, you reminded me - A really good landing is one where they can use the aeroplane again........

I really like this new coffee machine add-on......

I am migrating to electric power ("Shame" I hear some of you mutter!) after some 55 years association with i.c. I have a lot to learn as yet but have recently become aware of the "EagleTree MicroPower E-Logger V4" and its claimed abilities. With the aim of improving my own working electric knowledge base, and hopefully thereby increasing my success rate, it looks like a tool I just cannot do without! That said, the 'net reviews at times seem a little mixed. Is there anyone on the forum that has hands-on up to date experience of using this hardware that would help me decide as to whether to go ahead with purchase or not? Any assistance would be much appreciated. Operational compatibility with Windows 10 is something I am particularly interested in.

P.S. Now having a Sparrowhawk GRP cowl with (no longer required) cut-outs in it for a '61 ic, I contacted Seagull and enquired whether they would sell me a replacement. Good & bad news - Yes, but at 11usd for the item and 44usd postage! I may renew my association with home-brew GRP practices.....😏

My "Electric Sparrowhawk" has now had its first outing. It flew well and the landing was good enough such that "I can use it again"! For anyone else interested in maybe undertaking a similar conversion, my final powertrain comprised :- Overlander - T4260/06 motor, 500kV, 900W. Overlander 60A ESC Batteries - 2x Zippy 5.8Ah 3S (ie 6S total). 13x8 APC E-prop. Static max power consumption was measured as ~850W. At the field, a few club members sucked their teeth a little, wondering whether the 900W motor would be adequate; flying weight being a few ounces under 9lb. As a possible surprise to the gathered throng, me included, the initial take off run was quite sprightly and several S&L-ish orbits of the field followed whilst assisted trimming etc ensued. The initial flight timed out at around a little over 6 minutes, post one overshoot, and a successful landing completed. Electricity consumption is always a concern on first flights, but I was latterly further surprised to observe that each 3S battery was indicated as having 80% capacity remaining! Maybe I have over-egged the battery size a little. Hopefully, the above information will be of use to someone contemplating either a similar conversion or fresh installation.

FYI David, I acquired one of these about six months ago, complete with all servos installed. I fly it with a 3S 1300mAh LiPo and all works well. The only criticism I have is that with battery installed iaw internal structures, it came out somewhat nose heavy. I did not want to add a tail weight so had to modify the internal layout. Having moved the elevator and rudder servos back a little and with the LiPo positioned aft of the canopy, correct CofG was obtained with no tail weight penalty. You might like to consider this. Good luck!

A good landing is when you can walk away from the 'plane. A really good landing is when they can use the 'plane again......

Thank you Percy and Bob for your responses. The advice I have received is that, for this type of model, I should aim for 80 to 120 watts per pound. The Sparrow Hawk auw, including chosen motor, has worked out at 8.5 lb so we have the band required as 680 to 1020 watts. I opted for a 900 watt Overlander motor and am keen to see that power delivered to the prop. Using my watt-meter, I find that driving a 12x6 and 12x8, the declared power consumptions are ~700 and 800 watts respectively. I will try a small range of 13 inch props when they arrive. I should be able therefore to find a prop that causes the motor to reach its 900 watts potential under static conditions on max throttle but my initial enquiry is of course what happens after I let it go! Will the power delivered reduce; should I over-prop it for static conditions? Perhaps I am trying too hard but I have a desire to get matters as right as I can before I attempt a flight!

After a break of too many months, my attentions have returned to this project. Apologies in particular to Rich2 but the Sparrow Hawk now sports an electric motor. I am currently looking at which prop spec to go for. I can easily check maximum watt "consumption" of the motor v's prop dimensions under static (airframe) conditions to match motor power rating but, I am unsure what comparatively happens when the airframe gains speed and progresses to flight. For a given throttle setting, will the watts consumed increase, decrease or remain ~constant? Level steady flight assumed of course. Anyone any ideas?

Forgive me for adding my tuppence worth....... Call me pedantic if you like but frame rates of (eg) 22mS are referenced. Is this not more correctly "repetition period"? Is the example frame rate not actually 45.45Hz? I have experienced a couple of thread related issues with my Futaba T6J that may be of interest. I purchased a couple of the smaller Hitec servos and duly installed them in my T6J equipped model. On testing, I discovered they would follow some of the stick movement but not reliably and sometimes chatter. On contacting the suppliers and explaining the problem, I was asked whether I was using Futaba hardware! Returned and a change to Savox spec equivalents, problem resolved. Around the same time, I purchased two Orange 3-axis "gyros" (v2 if I recall correctly) to investigate what they had to offer. On the bench, they initially seemed to work as expected but fortunately I noted one issue. With the "gyro" activated, on only one of the channels and at one side of middle position, the servo would latch and not return when the Tx stick was centred. Move the stick in the opposite direction, and the servo would return and move as it should. Both "gyros" exhibited the same behavior. On changing the "sense" for that channel, the problem went away. By keeping that selection and orienting the "gyro" appropriately, it has flown several times faultlessly. The other two channels were fine. A little bit of 'scope investigation indicated the repetition frequency of my T6J to be ~80Hz, rather faster than the earlier established 50Hz standard. Could this be the issue? Do the respective Hitec and "gyro" firmwares have the capability to fully keep up with 80Hz? Are there other bits of aircraft kit out there that have frame rate limitations? Should manufacturers specify max frame rate? As a follow on, I contacted the "gyro" suppliers to advise them of my observations including full technical details - could cause an airborne problem I felt - and the response I received was effectively "Do you want them or don't you?"! Not very impressive really.......... Rant over!

Ummmm, super looking chap, but, in the days of Canberra were overalls not blue and bone-domes white?

No feedback so far regarding possible conversion of my Seagull Sparrow Hawk .61 1.6m ARTF to electric power.....

I am considering converting my Sparrow Hawk to electric power. Is there anyone out there who has successfully done so and able to offer some practical advice please? Even a reasoned "Don't do it!" recommendation would be helpful! Many thanks!

Thank you very, very, very much Kevin, copies received and printed. You're a star - take the rest of the day off!

Does anyone have a copy of the original RM July 1977 build article for the Voltair that they could scan and email to me please?