boleropilot Posted December 10, 2017 Author Share Posted December 10, 2017 600 feet - so with that altitude and an outside air temp of 29 degrees (in the SHADE) my pressure altitude numbers are: 35% decrease in climb rate and 45% increase in take-off distance required... winter only airfield ?????? bugger... Link to comment Share on other sites More sharing options...
farri Posted December 10, 2017 Share Posted December 10, 2017 winter only airfield ??????bugger... Google Earth shows 187 m which is 613 feet so 600 feet is good enough but why would you say "Winter only airfield?" Link to comment Share on other sites More sharing options...
boleropilot Posted December 10, 2017 Author Share Posted December 10, 2017 35% decrease in climb rate and 45% increase in take-off distance required on a 30 degree day will just make things a little tighter than on a 'cold' day at 20 degrees it's only 15% decrease in climb rate and 20% increase in take-off distance - all I'm sayin' m8 is that I need to be very much aware of hot days I tend not to fly on hot days anyway - I've nearly been sent inverted by a big nasty thingo I flew one wing into, so I tend to avoid hot bumpy days cheers m8, BP Link to comment Share on other sites More sharing options...
farri Posted December 11, 2017 Share Posted December 11, 2017 I tend not to fly on hot days anyway BP My question was meant to see if you understood Density Altitude. Density Altitude/Pressure Altitude,is what is occurring at the time and needs to be considered for each flight, regardless of time of the year or time of day....As far as I`m aware, there no Performance Charts for the Drifter so it`s better to err on the side of caution. Cheers. 1 Link to comment Share on other sites More sharing options...
boleropilot Posted December 11, 2017 Author Share Posted December 11, 2017 aha - the old chart I was using is titled Effect of Temperature and Altitude and does not mention a specific aircraft - in hindsight I can see that all aircraft are different and will react differently to the situation at the time the good news is that having discussed the matter with you I am now more aware of that aspect in relation to flying in/out of Woolly Field thanks for the input m8, much appreciated BP 1 Link to comment Share on other sites More sharing options...
mnewbery Posted December 11, 2017 Share Posted December 11, 2017 A quick stab at the Sporty's E6B for iPad suggests from a starting point of QNH 1008 hPa, AGL 1500 feet, OAT 38C, you get a density altitude of about 4500 feet which would be an extreme case. It would be a pretty unattractive thing to prepare a Drifter in those conditions then climb in and blast off. Relevant to this discussion, landing speed which is the true airspeed (TAS) is dependent on the pressure altitude. An indicated air speed of 55 knots becomes a TAS of 59 knots. The 7% increase in speed translates to a 15% greater energy that the brakes and drag need to dissipate for everything else to be the same. This would work for "generic air frame" at that speed. Of course a lighter air frame will have a lower minimum controllable airspeed and stop sooner. A four knot headwind would bring things back to equal. But that isn't the "fun" part! Without going into the maths too much, a density altitude of 4500 feet has reduced the number of air molecules for the engine to ~90%. For the Rotax 582 that would be like attempting to go around at 5500 RPM on a cold day. Not impossible but not ideal and certainly not something to do late in the game. So, flubbing it would be exciting to watch but not fun to do. If things went wrong they would do so more quickly with less margin for recovery than usual. I agree with BP in that on a cold(er) day with the right wind this would be a safe arrival and departure for the informed and thoughtful pilot. Many have proven that the mid-day flight is nothing like the morning flight and in this case is https://www.youtube.com/watch?v=OVM3RRd1vf0. (Youtube link to Stinson 108-3 crash) I guess it comes down to not letting the Drifter take you to a place (Woolooman airfield) that your mind hasn't already gone 5 minutes before, and survived. 1 Link to comment Share on other sites More sharing options...
boleropilot Posted December 11, 2017 Author Share Posted December 11, 2017 thanks mnewbery for your input, much appreciated... at least I know that if it all goes pear-shaped I will go to Pastafarian Heaven, where a beer fountain and a stripper factory await me..... cheers BP 2 Link to comment Share on other sites More sharing options...
mnewbery Posted December 11, 2017 Share Posted December 11, 2017 As you are no doubt already aware, crashing a drifter only guarantees you joined the long list of "people who have crashed drifters" It is no guarantee of surviving or anything else especially if you plan to aim between the trees. Stick it it high up then we can hang lights off it and call it a Christmas decoration 2 Link to comment Share on other sites More sharing options...
boleropilot Posted December 11, 2017 Author Share Posted December 11, 2017 sorry, I made a misteak - it's a beer volcano, not a fountain. For those of you who would like more information, look at: Flying Spaghetti Monster - Wikipedia cheers big ears Arr Me hearties ! Link to comment Share on other sites More sharing options...
boleropilot Posted December 11, 2017 Author Share Posted December 11, 2017 hey Farri - you a closet Pastafarian ? 1 Link to comment Share on other sites More sharing options...
mnewbery Posted December 11, 2017 Share Posted December 11, 2017 Beat me to it: Yes its a beer volcano. I also personally do treat September 19th as an auspicious day but the ceremony is brief and pre-dawn Link to comment Share on other sites More sharing options...
farri Posted December 11, 2017 Share Posted December 11, 2017 So here`s the situation! How many guys out there flying Drifters or dare I say, any other R.A.A. registered aircraft, know how to calculate Density Altitude/Pressure Altitude, even if you can do the calculations, if you can`t apply it to the particular aircraft, at the time, all you have is a lot of figures. Frank. 1 Link to comment Share on other sites More sharing options...
mnewbery Posted December 12, 2017 Share Posted December 12, 2017 I actually like doing the maths so count me in. Likewise for the application of the numbers based on the POH or similar. 1 Link to comment Share on other sites More sharing options...
farri Posted December 12, 2017 Share Posted December 12, 2017 hey Farri - you a closet Pastafarian ? ...You`re ahead of me, I just had to find out what a Pastafarian is.....Flying Spaghetti Monster - Wikipedia.... Link to comment Share on other sites More sharing options...
boleropilot Posted December 12, 2017 Author Share Posted December 12, 2017 honestly, we could fix global warming if we could just get more pirates - not the nasty ones (like those damn Somalis) but just normal (?) guys who dress like pirates occasionally... and talk like a pirate on 19th September !!!!! avast ye scurvy landlubbers - more beer, and bring on the wenches !!! BP 1 Link to comment Share on other sites More sharing options...
farri Posted December 12, 2017 Share Posted December 12, 2017 I actually like doing the maths so count me in. Likewise for the application of the numbers based on the POH or similar. Back in the late nineties, I did some flying out of private property up at Kaban Nth Queensland, elevation, 3,100 feet.The guy was a club member of ours..I used to be able to chalk up the figures but now, I`d have to refresh it all...These day, all my flying is done from my own property, which is 2 meters AMSL. Link to comment Share on other sites More sharing options...
SSCBD Posted December 12, 2017 Share Posted December 12, 2017 Just a quick note as have little time before I am out. I don't know how many hours you have flying, or in a drifter, but I assume from the question not thousands as Frank has so listen to him. However a safe way. Poor mans way to convince yourself, the dangers of hot weather 30 to 35 degrees c on limited runway length. I suggest yo find a nice strip with elevation don't care but lets say you want one around your 600ft elev. Mark out you length available with a line on the side of the strip, using bag of flour and make say 50 meters before the end as well, you want that line to be airborne THEN on a nice hot day over 30c to say 35c Try a few take off and landings hopefully with little wind say 2 to 5 kts max . Then also try a few downwind AND SEE the huge difference as well, including rate of climb if the wind is 2 to 5 kts . Take a go pro and lets us know how you faired and post the distances you got. Also try a landing without brakes, as always assume they will fail. Unless you trust in god. (not being rude.) 1 Link to comment Share on other sites More sharing options...
boleropilot Posted December 12, 2017 Author Share Posted December 12, 2017 200 hours m8, primarily on the Drifter - as above, I will be conducting a great deal of practice (mainly at Roadvale, some at Boonah) and a lot of missed approaches at home before the wheels touch down at Wooly I've even been practicing with the flight simulator, mainly due to the fact that the Ant's Drifter has been finely tuned for the most accurate flight envelope possible - you can even sideslip it... As far as Boonah is concerned I've checked the dimensions for 200 metres and have been practicing with the sim using all sorts of approaches The sim of course is a far cry from the real thing and I for one would not put any trust in the results, but it is amazing how accurately it flies (and how easy it is to stall when mucking around with this stuff) Looking forward to getting 0455 back in the air in the new year and getting back into the saddle - fingers crossed the 'near' new 582/99 will have a lot more herbs than my old grey head motor thanks for the input, much appreciated m8 cheers BP 1 Link to comment Share on other sites More sharing options...
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