Cirrus SR20 info

Markus,

I like your Hotshot Commander. Could you possibly share some more details?

-where is the critical altitude of the turbo?
-Is the picture above WOT?
-120KIAS looks like it almost 160 true up there. It that what you max out at?
-do you have Gamis? Do you run LOP at all? If not, what are the CHTs like up there?
-what climb rates do you get at MTOW? CHTs in the climb?

2. Pilot technique…ball centered, best rate of climb speed for the givem altitude, etc.

Very true, especially best RoC (Vy) and best angle of climb (Vx) converge as you approach absolute ceiling. A lot of fixed prop aircraft don’t make service ceiling because the pilot may be using the equivalent of Vy at sea level, when Vy at, say FL100, is probably 10-15 knots less (IAS).

Even an unmodified Super Cub got to 30,203 feet back in the 70’s.

mdoerr wrote:

In Antwerp I had a valid GS indication in FL150 and about 48NM to run.

Of course the glideslope is usually only certified for use up to 10nm from the threshold, unless it is specifically extended to a higher usable distance (never 48 nm). :) So “valid” means “not flagged” in this case.

I can pick up the Lydd EGMD ILS at 25nm. This is sometimes used for avionics tests. Their IAP has a DME arc at 14D and the platform is 3200ft.

You all must have very sensitive GS receivers 8-)

With the KN75 I once recorded key receiver signals during an approach to LSZH ILS28. At GS intercept the signal strength was less than 10dB above flag sensitivity – not exactly much.

boscomantico wrote:

-where is the critical altitude of the turbo?
-Is the picture above WOT?
-120KIAS looks like it almost 160 true up there. It that what you max out at?
-do you have Gamis? Do you run LOP at all? If not, what are the CHTs like up there?
-what climb rates do you get at MTOW? CHTs in the climb?

Unlike the 112TC the Hotshot is a turbo conversion of an injected IO-360 with a manual waste gate. So I’ve got a Cessna style vernier control for the waste gate. My 112 is a B model and shares the long wing with the 112TC which is ideal for a conversion.

I’m not sure about the critical altitude as the waste gate is not fully closed at FL190 and I can get 100% power. The maximum continuous power above 10k is about 80% with 25in MP.
In this picture it was ROP operation (fuel flow is about 12gal/h) 160TAS is what I get at FL150/160 and matches the performance figures in my POH. POH adjustments are not great, there are many gaps in figures. In the amendment is a blanket sentence: Plane matches or exceeds performance figures. It better does.

I do not have GAMI, but my I can run it LOP and I do it now. I loose about 8 knots, but I’m down to 9.5gal/h CHT are about 328 to 339 (last flight 2 days ago), but the limiting factor is TIT was 1580 and much lower than running ROP. Limit is 1650.
In ROP operation I sometimes have to go up to 14gal/h to keep TIT under its limit.

Main problem in the climb is oil temperature not CHT. CHT usually stays in 370s to 380s. To keep oil temp low I fly 95kts with 700fpm. Vx is 78kts and Vy 88.
It is possible to use overboost for 5 mins up to 31inMP together with Vy it gives you about 1200fpm.

There are 2 downsides of the plane.
1. no deicing. It is theoretical possible with weeping wings, but not economical as the conversion cost more than the hull value.
2. heating. It is not that cold but warm is different. We have done some tweaking with the system as there is an airbox where hot and cold air get mixed, but it has direct contact to the outer skin, so all heat is lost. We bypass this airbox with a hose now and we have some heating. So up to 40C difference is possible now. Sounds a lot, but but with OAT of -30 it is cold inside.
Next thing to fix are the cold air hoses in the ceiling, which are a bit leaking after 39 years.

After all it is the most comfortable aircraft I have flown. Legroom and the feeling of personal space are not replaceable.

You should try a Cirrus then. ;-) (obviously, it’s in a different price league)

I have only once flown in a 112 and while the cabin width felt even bigger in the Commander, the big windows and overall cabin design makes the Cirrus the number one in creature comfort.

Oh, and by the way, even in the Cirrus, the heating is insufficient, at least for those in the rear seats.

Good info on the Hotshot, very interesting. Thanks a lot.

C182 to SR20 is a downgrade…

…only in horsepower, short field performance and loading capability.