Hi there,

For the all seasoned flyer's; does anyone has problems when flying in freezing temperatures? I just read Tom Antlfinger's maiden flight with his friend's Compo Bandid at very low temp's and I remembered my cold day flying experiences. (By the way, congrats's Tom, first flights are always exciting!)

Normally my homebuilt KJ-66's are very reliable and safe performers and when it's not freezing I like to fly them a lot. (And that's very often in Holland!) In the beginning of my turbine experience , back in 1995, I had some problems and unexplainable flame-outs when flying in freezing conditions and decided never to fly again when temperatures are below 3 degrees Celsius. (At that time I also did not use any ECU!) This is also better for the ABS components on the airframe which can become quiet brittle and fragile at those low temp's. Also the propane starting gas bottle doesn't have to be warmed before the start. I did some checks on water contamination and couldn't find anything. (As an aircraft maintenance engineer I have access to some reliable water detectors.) As Holland can have a quiet moisty environment I thought about icing the engine's inlet but this should be very unlikely?

Reading Tom's flight I supposed that many jet jockeys have more freezing day's than I have and still would like to fly a lot. So please tell me, just out of curiosity , how are your experiences?

Gerald Rutten.

Hi Gerald:

I have not had any icing problems. I do keep my fuel in my heated car between flights, and only put it into the tanks, just before lightoff. I also keep my Powermax warm in the car.

The P-120 runs perfectly every time.

I share your concerns about the cold on the fuselage and wing material, but from composite giant scale experience, the new materials do well.

I have not flown below absolute temps of 25 F/4 C because my hands can't take the cold, and I don't like flying even with thin gloves.

I posted a couple more photos taken today on my Compo Bandit thread. Some guys didn't believe I actually fly, but just took that photo in the driveway.

Tom

Tom,
I woke this morning to find the grass was white....We had a light snow fall over night.......Won't be flying tomorrow as listening to the weather it is going to be 2c and 20mph winds so it will prob feel like -6 wind chill.
Still have only been flying once since Lake wales, awaiting deccent weather.

Laura

Hi Laura:

Well, as you can see from my latest photos, no snow on our field as of today, but we are expecting 2" of ice/snow tonite, so my flying days are numbered, although it is supposed to warm above freezing again next mid-week.

That Lake Wales weather had to be the best.....I am not sure we appreciated enough then...

Take care, and stay warm


Tom

G'day Gerald, Interesting thread this! I am also very interested to here about possible turbine thrust gains at the lower ambient air temps.
I was running a PST J600/TEMS ecu on Thursday here in Southern Ontario on the test bench with an the ambient air temp -7c all went well, and the little turbine did not miss a beat....although I did not see any significant difference in thrust from warmer summer temps.
I would not hesitate to fly the J600 in these temps except for the frost bite factor to my fingers...and lack of skis for my ROO!

I flew the maiden flight of the Eurosport with an air temperature of -4degrees, the AMT NL Pegasus did not miss a beat.
I have often worried about icing, but so far I have flown throughout the british winters without a problem. I intend to fly tomorrow, the temperature in the North will be below freezing, maybe I'm pushing my luck ?

Mark Diggle

When it gets below 35 degrees F, the rule is bring your friend who also has a turbine. Find someone who doesn't fly much, just piddles. Have him fire up "often" and use his turbine for your heat source. They work great for toe, hand, etc. heaters. Remember Superman 12 it was cold, the startup area always had several guys behind the startup birds getting warmed up.
Lee H. DeMary

PS Or just move about 2,000 miles south for the winter, hummm wouldn't that be nice --------

Hello Guys.

I'm new here, but I thought I'd share a couple of problems I once had when manually starting a turbine when it was cold & frosty, about -1'C.

Especially if you manually start your turbine with air & propane:

Starting rpm too low:
Make sure the air regulator on your scuba bottle works at low temp. Mine is for operation >= 10'C, below that it doesn't regulate properly and gives low flow/pressure.

Combustion chamber pre-warm not getting hot enough:
Keep your propane bottle warm,otherwise the vapour pressure will be too low. (e.g stick it down your pants etc, not inverted or you might get a wet start !)

But please don't use forced heating on your air/propane bottles.

My humble tuppany's worth.

yes, you are all right about the cold fingers at those flying days, probably a good canteen close to the strip will do some help !

On the test bench I also never experienced any faults, running it below -10 Celsius. The intake always stays above 25 Celsius and has so his own de-icing system. Spartan is right about keeping your equipment in operating condition and I liked Tom's idea of storing it all in the car.

The last few weeks have been terrible in Holland (Lot's of showers !) and now things are calm, but freezing. My fingers are itching so I guess I'm gonna take the chance after all these years, This hobby was all about experimenting wasn't it?

Greets, Gerald.

Intake icing due to the drop in temp due to the pressure reduction in the intake can be a serious problem.

Rolls Royce, P+W and GE all call for engine anti-icing when :
Ambient temp below plus 10 C.
AND there is rain, sleet, snow or visibility less than 1 mile !
Dont have the problem in Australia !!
BRG, David Gladwin.

Hi David,

yes I'm aware of the problems on the full sizes as I trouble shoot these machines daily but I don't think this could be the case on our turbines. Our engines are very little, making heat transferring through the engine easy. On my test bench I still have a 30 degrees Celsius temp. on the intake, while running at -13!

So in this case the whole engine has it's own de-icing system. Also when I experienced the flame outs a few years back they happened in clear blue sky with almost no snow on the tarmac.

Maybe I also could solve things when moving down under , are there vacancies on aircraft maintenance engineers out there?

Thanks, Gerald.

Well thats interesting. However, the cooling effect of airflow in flight MIGHT keep the intake cool enough to allow ice formation in the right humidity, temp. conditions. . Why it should happen in clear air though is a mystery.

There were several unexplained flameouts last year at Winter jets, again in clear air. I dont have any more suggestions !

After the Ansett colla[se theres a surplus of engineers here !
BRG, David Gladwin

I had three really good flights today here in England, at Wroughton. It was zero degrees C at 500'above sea level and with the wind chill was minus 8. I had no problems at all with my AMT (NL) Mercury HP and the thrust was just amazing. It is interesting just how reliable all our equipment is, batteries that a few years ago would have died very quickly,etc.

As Tom said the biggest problem is keeping your hands warm, oh well not long until Florida jets......

Hey Jonathan,
Me dad and I dont go out under 10c........Aint enjoyable in cold.....
Have only been flying once since Lake Wales.

Laura

I seem to recall an article in RCJI concerning many unexplained flameouts at a jet rally held in cold weather. (Winter Jets in the U.K.?) If I recall the only explanation for the flameouts on normally flawless running engines was icing. The trouble was that the evidence melted by the time the model was retieved due to residual heat from the turbine. Maybe we'll never know!?!

Kevin

When flying the other day at 0 to -2C, after landing, my entire bypass was still warm, even up front. Undoubtedly there is some reverse air flow due to turbulence and back pressure, as well as some heat conducted thru the bypass itself. I know the BVM bypass design is nice, but I doubt flow is uni-directional laminar, through the bypass at all times.

Hopefully this keeps ice off the inlet. Additionally, up here in the winter, the air is not only cold but extremely dry with dew points of -10C or lower, making icing less likely.

So far, the Electrodynamics Battery Backer is working as advertised. I am using (2) 1400maH 5-cell JR Extra packs. They come off the Graupner charger at about 6.8-7.2 volts, but shortly after turning on the Rx and loading the circuit, the "surface charge" dissipates, dropping down to about 6.5 volts. With the intrinsic 0.9v drop in the backer, I take off at about 5.6 volts at the receiver bus, and land at about 5.2volts under load. It takes about 300maH/flight symmetrically out of the packs, i.e. about 150 out of each pack according to the readout on the Graupner charger.

I still think I am probably overkilling, but the money involved in a jet loss always seems to breed overkill in the systems. The last time I lost a plane due to battery failure was on a glider at Torrey Pines in 1970. And that wasn't all that bad since to retrieve the plane below the bluff on the beach meant crossing a nude beach!! It took me a while to find that plane!!

Tom

BUMMMMMMMER!!!!!Ha Ha.