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Extreme Flight Owners

O

orthobird

150cc
Liberty10;18575 wrote: I have the DA35. I took IR gun readings that all looked normal the first week. Now I have a sensor for realtime temps. I placed the sensor in the second from the top fin space and it is on the back side of the cylinder. Temps the first time were 295° peak. It worried me a bit but the IR gun temps still read normal on the ground. Anyway in much cooler temps on Saturday (70°F) the temp peaked at 260°F. I'm planning to add a baffle that will put air thru the fins from on side to the other. We'll see if this lowers the rear head temp or not.
Click to expand...




do not be worried by that "true" temp. what i mean is, that traditional thought on using IR guns and measuring temps on front of cylinder, in my opinion is erroneous. SO, the "standard" values are an underestimate of real world temperatures.



at what temps should we get worried?



this is the million dollar question....



i can tell you this, and i do not suggest you do this,



but i was running my DA 70 with good baffles ( i thought) and on a day with ambient temps in 95, the sensor in back of cylinder, as close to spark plug as possible, during flight, temps got up to 400 F, and once it got to 450 F, the engine began to fade.



this tells me, 400 F, it was doing fine, 450 F is too hot!!!



with that said, if your temp on the front of cylinder ever got to 400F, that means that temp in back of cylinder is even hotter, and i mean, by 80 to 120 degrees hotter (ouch), you are looking at seizure time.



in any event, i then re did the baffles, i opened the bottom of the tunnel for the pipe, which i do not have, and i placed a air dam in front of one of the openings, and now, temps are in 280 to 300 range!!!



it is critical to have at least 3 to 1 on the area of air exit relative to inlet area.

and then, creating some form of air dam, that will help create an area of negative pressure, and thus extract the hot air out!! this will dramatically help in cooling your motor and preventing motor performance fading, oil breakdown and lack of lubrication, excessive carbon buildup, and potential seizure.



the cooler you keep that engine temps at, probably the longer it will last.





your peak temp of 295 in the back of the cylinder is not worrisome at all.

but do try to make baffles and help the hot air get out, and i bet your temps will drop to 260 max as peaks.





i have a DA 35, and these are my temps on it:





6/1/14

Engine: DA 35 cc with pitts muffler

Fuel / oil mix: 40 to 1 redline, 91 octane

altitude: 200 feet

ambient temperature: 87 F

prop size: 20 x 8 Xoar wood

air frame: 78" extreme flight extra 300

radio system: Jeti



data:

1. highest cylinder head temp during flight (not after landing): 357.9

2. temp range 309 - 357.9 F

3. temp on landing and taxing back = 280 F
 
Xpress

Xpress

GSN Sponsor Tier 1
Anybody around here have an electric EF 88" Yak? I bought mine from Ryan Archer who had an electric setup in it but i'm wanting some help setting up a different power system. I think he had an A60 series motor in it. I'm hesitant to put a gasoline engine in the airplane because it's aged a bit, even though it hasn't been flown above mild aerobatics, let alone more than a dozen times.



It already has a battery tray in it for dual 5s packs and the motor mount for the electric motor so setting it up as an electric again shouldn't be a big problem.
 
emtp275

emtp275

100cc
I have yak fever for some reson and I am thinking about the 91 from EF, any one that has one let me have it, the good and the bad looking for it honest
 
O

orthobird

150cc
emtp275;18678 wrote: I have yak fever for some reson and I am thinking about the 91 from EF, any one that has one let me have it, the good and the bad looking for it honest
Click to expand...


i have it and it is awesome!! all good. DA 70 on it. one of my funnest planes to fly. it can d wicked 3 d stuff. well, i do not have to tell you this alone, i am certain others will agree. the construction of the airplane is very good. it has CF stringers on the bottom of the fuselage. it has a tunnel for a pipe/can as well. i cannot think anything negative to say about this airplane, except it is hard to find!!! you need to be looking at the website every day til it pops up!! just checked...... they are in stock now for 700 dollars!!!

if you use a twin, like the 70, you will have to make a small opening in the left side of the cowl for the spark plug cap.

when i got mine, i did some reinforcements to the dowels in the canopy that connect with the front of the fuselage. just so i do not have to worry about that coming undone. other than that, i cannot think of anything negative to say about it. mine has about 70 flights on it.



https://www.youtube.com/watch?v=aiyVxXC0mRc&list=UUZYrMHmbHD9fMkFu1exq6Cw

18742=12552-IMG_5975.jpg
18742=12552-IMG_5975.jpg
 
AEROSHELDON

AEROSHELDON

70cc twin V2
Awesome video! I have 13 flights on mine so far and I love it!



Those vids make me want to fly more, they are just so cool.
 
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