Normally aspirated? Ops... Never heard before from someone cruising at that altitude with a non-turbo aircraft.
The TB20 will go to FL200 in ISA conditions
Typical operating data is (ISA+15 recently)
FL190 TAS135 8.2 USG/HR 2575 RPM
FL170 TAS138 9.0 USG/HR 2575 RPM
FL110 TAS149 10.3 USG/HR 2400 RPM
The above is peak EGT. However anything above about FL180 needs 120F ROP or so (best power) unless the air is nice and cold.
My usable fuel is 86.2 USG.
It takes about 30 mins to reach FL160. FL190 takes another 15 mins maybe, depending mainly on temperature. In ISA+15 the ceiling goes down to about FL180, which corresponds to the 8C=1000ft guideline posted on the other thread here.
Yeah... a turbo would be good but there is other price to pay for that.
Why did that Arrow do only 600fpm in climb? That is about 50-60% of what I would expect.
I didn't know that you can really use the upper levels with a non-turbo aircraft. I thought that they operate best between 7-10K ft.
Why did that Arrow do only 600fpm in climb? That is about 50-60% of what I would expect.
AFAIK this is the usual rate. I've compared it with many others... And I had all the LoPresti speed kits installed. The POH seems to state a higher rate but that's all with max continues power setting which is different from cruise climb with 104 KIAS.
You can see that in the video clip linked in my previous post. To maintain cruise climb speed I often had to reduce climb rate to 400 fpm because KIAS went below 100. And I was alone in the plane! This was really annoying.
You can also see all the temps, FF etc at LOP and 100 ROP. Sense of this clip was to gather all these data at the ceiling of 20K ft. Difference between LOP and 100 ROP at FL200 is: +18 kts speed, +4 GPH, -80F TIT.
Edit: 104 KIAS cruise climb is equal to 75% power. Later, when I had installed an intercooler, I was using 80-85% in climb because of the lower temps. I remember getting about a continuous 700 fpm there.
I never do "cruise climb". It is sub optimal in every way.
The best way is to do a "constant EGT" climb - as described here.
It's a very good method, which allows you to climb all the way to the operating ceiling, just by changing the mixture. The other two stay fully forward.
One can cruise climb to some sort of medium level but the only way to reach the operating ceiling is by flying at best-power at the end, and no cruise climb is going to assure that, other than by accident.
Obviously the above is only for a NA engine; a turbo engine is a completely different thing.
As regards yesterday's wx, it would be interesting to get the archive from SAT24 and look at their cloud tops overlay. The actual tops were FL190, over say NE France.
The above is peak EGT. However anything above about FL180 needs 120F ROP or so (best power) unless the air is nice and cold.
Is there a modification for the TB20 to improve cooling airflow? For an engine that size, the airflow is rather limited and it is static (no cowl flaps). I think it would be quite an improvement to add cowl flaps to the TB20.
Why did that Arrow do only 600fpm in climb? That is about 50-60% of what I would expect.
It's only got a TSIO-360, 4 cylinder with 200hp. The speed of an aircraft is mainly determined by its fuselage and wings whereas the engine horse power determines the climb rate. Best example is the C172. You get it with 150hp and with 210hp (Reims Rocket) and both have almost the same cruise speed but the latter climbs almost vertically.
No mod I know of, but sorting out the baffles really well helps. I have used two different materials on mine.
However the ROC is almost the same at 120kt as at 95kt.
I would have thought that the ROC is a transfer of excess thrust into potential energy, so the main factors should be the engine power and the aircraft weight. That's assuming you climb at a given point on the curve, say Vbg.
What is the weight of this 200HP Arrow?
What is the weight of this 200HP Arrow?
2900 lbs MTOW.
Using cruise climb is according to the POH - although a Mooney with the same engine is allowed to use full power until level off. A T-Arrow is only allowed to do that for 5 minutes.
Using cruise climb is according to the POH - although a Mooney with the same engine is allowed to use full power until level off. A T-Arrow is only allowed to do that for 5 minutes.
I can understand that for a turbo aircraft, where one climbs much or most of the way to the ceiling using the surface power settings, supposedly.
The Arrow is quite heavy. The TB20GT is 3086lb which is only 6.4% more but it has 25% more power. So I guess the excess thrust is a lot more.
The TB20GT is 3086lb which is only 6.4% more but it has 25% more power. So I guess the excess thrust is a lot more.
That depends on the turbocharger, the TB20 is down to 200hp quite soon after MSL whereas the Arrow might be able to keep it for longer. I can keep my 235hp up to FL200.
Sure, but I was speaking of the sea level climb situation.
250HP into 3086lb is a lot more than 200HP into 2900lb.
