Carson speed
Moderators: Rick, Lance Murray
- Trigger
- 1 Diamond Member
- Posts: 6
- Joined: Wed Oct 03, 2018 11:28 am
- First Name: Luis
- Aircraft Type: DA42-VI
- Aircraft Registration: TBN
- Airports:
- Has thanked: 1 time
Carson speed
Hi guys, I am new at the forum but I've been following it for a while.
As Diamond doesn't provide best glide to "compute" Carson Speed, based on your experience what you be the speed (and power settings) for a very long flight (around 1000 NM).
I've made some trials and I figure out that L/Dmax is around 90/95 Kias meaning (according Carson speed) best range speed will be around 118/125 Kias (35/40% power setting). Does this makes any sense?
Thanks
As Diamond doesn't provide best glide to "compute" Carson Speed, based on your experience what you be the speed (and power settings) for a very long flight (around 1000 NM).
I've made some trials and I figure out that L/Dmax is around 90/95 Kias meaning (according Carson speed) best range speed will be around 118/125 Kias (35/40% power setting). Does this makes any sense?
Thanks
- dgger
- 4 Diamonds Member
- Posts: 218
- Joined: Sun Feb 21, 2016 11:00 pm
- First Name: Peter
- Aircraft Type: DA62
- Aircraft Registration: OEFGM
- Airports: EDLN
- Has thanked: 21 times
- Been thanked: 39 times
Re: Carson speed
My gut feeling and some preliminary measurements in a DA42NG, which I took for an Atlantic crossing, suggest it is a bit higher than 35/40% - at least, if you're anywhere near MTOM.
I found that airspeed fluctuation increase significantly when pulling back, so getting good measurements was a bit of a challenge. Nevertheless, at MTOM (1,900kg in my case) 45% gave me a clear improvement in range over 50%. Lower than that yielded mixed results. My speeds were a bit different, though. At 45% I get about 125-ish KTAS at 10,000ft IIRC.
The most interesting data point I could find so far was this: http://www.diamond-air.at/en/media-cent ... -non-stop/. Apparently, you get best range in a TDI at 42%
I found that airspeed fluctuation increase significantly when pulling back, so getting good measurements was a bit of a challenge. Nevertheless, at MTOM (1,900kg in my case) 45% gave me a clear improvement in range over 50%. Lower than that yielded mixed results. My speeds were a bit different, though. At 45% I get about 125-ish KTAS at 10,000ft IIRC.
The most interesting data point I could find so far was this: http://www.diamond-air.at/en/media-cent ... -non-stop/. Apparently, you get best range in a TDI at 42%
- ememic99
- 5 Diamonds Member
- Posts: 1086
- Joined: Wed Apr 09, 2014 10:31 am
- First Name: Emir
- Aircraft Type: DA42
- Aircraft Registration: SEMAD
- Airports: LDZA LDVA
- Has thanked: 205 times
- Been thanked: 393 times
Re: Carson speed
Original TDI with 42% hardly can achieve 152 kts of TAS (at 10.000 feet you need around 70% to achieve that) - obviously heavy tailwind was involved in this crossing And 42% yields 3 GPH per engine a bit more than stated.dgger wrote:Apparently, you get best range in a TDI at 42%
From article: "Guillaumaud set engine power at a fuel conserving 42% and achieved an average ground speed of 152 kts."
- dgger
- 4 Diamonds Member
- Posts: 218
- Joined: Sun Feb 21, 2016 11:00 pm
- First Name: Peter
- Aircraft Type: DA62
- Aircraft Registration: OEFGM
- Airports: EDLN
- Has thanked: 21 times
- Been thanked: 39 times
Re: Carson speed
According to the POH 50% in ISA conditions at 10,000ft should be give you 127 KTAS. I would assume they easily had 40 knots average (!) tailwind. That's the way to go for your 1000NM leg. But pray for the weatherman to be infallible...ememic99 wrote:Original TDI with 42% hardly can achieve 152 kts of TAS (at 10.000 feet you need around 70% to achieve that) - obviously heavy tailwind was involved in this crossing And 42% yields 3 GPH per engine a bit more than stated.
The reason I mentioned the press release is not because of the accurate data, but because pilot for the PR stunt with the assumed backing of the Diamond engineering team deliberately chose 42% - which for the prevailing condition I take to be the best available choice i.e. the maximum range speed that OP had asked for.
- ememic99
- 5 Diamonds Member
- Posts: 1086
- Joined: Wed Apr 09, 2014 10:31 am
- First Name: Emir
- Aircraft Type: DA42
- Aircraft Registration: SEMAD
- Airports: LDZA LDVA
- Has thanked: 205 times
- Been thanked: 393 times
Re: Carson speed
It really requires patience to fly 125 kts in aircraft that easily can do 50 kts faster
- dgger
- 4 Diamonds Member
- Posts: 218
- Joined: Sun Feb 21, 2016 11:00 pm
- First Name: Peter
- Aircraft Type: DA62
- Aircraft Registration: OEFGM
- Airports: EDLN
- Has thanked: 21 times
- Been thanked: 39 times
Re: Carson speed
Sure does. However, the upside of not having to use a raft has been a sufficiently strong incentive on my longer legs.
- robert63
- 3 Diamonds Member
- Posts: 152
- Joined: Sun Dec 28, 2014 8:53 am
- First Name: Robert
- Aircraft Type: DA42NG
- Aircraft Registration: OE-FAR
- Airports: LOWL
- Has thanked: 14 times
- Been thanked: 24 times
Re: Carson speed
The Gyronimo App for the DA42NG gives the best range at 18.000 ft with 50% power setting. The range at ISA and 0 wind is 1.119 NM. Speed is 142 KTAS at 8.7 Gal/h. The 30 Minutes reserve is not included. The App is quite accurate for our aircraft.
- Henrik
- 4 Diamonds Member
- Posts: 228
- Joined: Tue Jan 18, 2011 2:08 pm
- First Name: Henrik
- Aircraft Type: OTHER
- Aircraft Registration: NONE
- Airports:
- Has thanked: 4 times
- Been thanked: 11 times
Re: Carson speed
Agree completely - I've experimented quite a bit as well (in a -VI) & also feel that around 45% at FL180 is the sweet spot for max range.dgger wrote:My gut feeling and some preliminary measurements in a DA42NG, which I took for an Atlantic crossing, suggest it is a bit higher than 35/40% - at least, if you're anywhere near MTOM.
You can drop it down below 40%, but the high angle of attack give the airframe a sluggish feel & you feel a tendency of continuously chasing small up & down drafts, which surely can't be efficient. 35% power is really for max endurance & not range.
Also they used a 26 gal ferry tank. Impressive distances none the less.dgger wrote:The most interesting data point I could find so far was this: http://www.diamond-air.at/en/media-cent ... -non-stop/. Apparently, you get best range in a TDI at 42%
Yeah. I generally don't mind long flights. But needing to *deliberately* fly 30-35 kts "slower" for 6 hrs gets kinda old after having done it many times. If you need frequent 1100 nm non-stops, the DA42 is just not the ideal plane. Those missions brings you into M600 territory.ememic99 wrote:It really requires patience to fly 125 kts in aircraft that easily can do 50 kts faster
- ememic99
- 5 Diamonds Member
- Posts: 1086
- Joined: Wed Apr 09, 2014 10:31 am
- First Name: Emir
- Aircraft Type: DA42
- Aircraft Registration: SEMAD
- Airports: LDZA LDVA
- Has thanked: 205 times
- Been thanked: 393 times
Re: Carson speed
For this FF (8.7 GPH for both engines) at 18.000 ft TDI achives these numbers (recorded during 500 hours with CD-135 and 100 hours with CD-155):robert63 wrote:The Gyronimo App for the DA42NG gives the best range at 18.000 ft with 50% power setting. The range at ISA and 0 wind is 1.119 NM. Speed is 142 KTAS at 8.7 Gal/h. The 30 Minutes reserve is not included. The App is quite accurate for our aircraft.
- CD-135 - 60% load, 142 KTAS, 1247 NM
- CD-155 - 52% load, 146 KTAS, 1282 NM
Zero fuel distances were not measured those are only calculations.
- ememic99
- 5 Diamonds Member
- Posts: 1086
- Joined: Wed Apr 09, 2014 10:31 am
- First Name: Emir
- Aircraft Type: DA42
- Aircraft Registration: SEMAD
- Airports: LDZA LDVA
- Has thanked: 205 times
- Been thanked: 393 times
Re: Carson speed
Fully agree and that's why I'm trying to limit my legs to 800 NM, flying at 70-75% load which gives 169-174 KTAS at FL180 and FF 12.0-13.2 GPH (the engines are CD-155).Henrik wrote:If you need frequent 1100 nm non-stops, the DA42 is just not the ideal plane. Those missions brings you into M600 territory.