Aircraft Speeds
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Aircraft Speeds
Hi!
Hope everyone is well and making better use of the VMC than I am at the moment!
what are people's opinions on flying aircraft en route above the normal cruising speed for any length of time given the right conditions?
For example the Cruise of a C172 is about 120kts Vne is 163kts. If conditions were right. What problems would I encounter flying for an hour Straight and Level at 145-150kts IAS?
This being from a Renters perspective rather than an owner.
Cheers!
Hope everyone is well and making better use of the VMC than I am at the moment!
what are people's opinions on flying aircraft en route above the normal cruising speed for any length of time given the right conditions?
For example the Cruise of a C172 is about 120kts Vne is 163kts. If conditions were right. What problems would I encounter flying for an hour Straight and Level at 145-150kts IAS?
This being from a Renters perspective rather than an owner.
Cheers!
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If you rented it wet who cares if you firewall the throttle but I doubt you would get anywhere near those speeds. The A/c owners would not be over excited if they did some calculations from the log sheets.
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Well, you'd probably have trouble retrieving the throttle from behind the instrument panel where you had to push it to go that fast.
Seems a bit pointless really. Why not rent a quicker aircraft?
Seems a bit pointless really. Why not rent a quicker aircraft?
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Who cares? Maybe the next person to hire it!
I don't know about other types, but I reckon you would only get another 10kts-odd out of an Archer if you flew with throttle to the wall. Hardly worth it, I wouldn't have thought.
Vne is a structural thing as far as I'm aware - ie. stick a 172 in a dive and you will get there but certainly shouldn't exceed it. You ain't going to get there without gravity though!
I don't know about other types, but I reckon you would only get another 10kts-odd out of an Archer if you flew with throttle to the wall. Hardly worth it, I wouldn't have thought.
Vne is a structural thing as far as I'm aware - ie. stick a 172 in a dive and you will get there but certainly shouldn't exceed it. You ain't going to get there without gravity though!
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More of a hypothetical question really, but even flying 130KIAS as opposed to 120 makes a difference on a trip to central spain!
Obviously renting a faster plane is the option. But most aerodromes which have numbers of flying schools only have 172s and Archers to rent out. I rarely see any "pokier" SEP about.
Obviously renting a faster plane is the option. But most aerodromes which have numbers of flying schools only have 172s and Archers to rent out. I rarely see any "pokier" SEP about.
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I can't help feeling looking at things from a renters rather than an owners perspective is a tad selfish. If you burn more fuel than is necessary it will just put up the hiring charges for everyone, yourself included.
And I wouldn't be too happy to have the donkey stop one day because someone hasn't been treating it properly.
As M14P says, if you are worried about flight times, hire a faster aircraft. For longer flights an aircraft that costs more per hour but cruises faster can often work out cheaper in the end.
And I wouldn't be too happy to have the donkey stop one day because someone hasn't been treating it properly.
As M14P says, if you are worried about flight times, hire a faster aircraft. For longer flights an aircraft that costs more per hour but cruises faster can often work out cheaper in the end.
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A typically proonish off-the-wall question 
Hopefully, this is a more sound answer!
This is what it says in a copy of a POH, which I have in my possession:
"Throttle settings in cruise:
a) Whilst a moderate throttle setting will ensure the maximum range, an aircraft's speed is one of its main advantages.
b) When calculating the required throttle settings for a journey, the pilot will take into account the meteorological conditions and his/her own capabilities.
NOTE: When flown within limits there is no mechanical reason for not setting the throttle for a fast cruise."
So, why, why not?
1. Faster mean more fuel burn. Moderate means greater range.
2. School FIs can recommend settings like 2200 or 2300rpm. I wouldn't redline the throttle (ona fixed-pitch prop). 100rpm off for a fast cruise would be mechanically okay in the case of the a/c above
3. Your human capability of handling a faster speed.
4. Enviromental conditions.
Check the POH for engine handling/cruise tips. You have read the POH, haven't you?
Hopefully, this is a more sound answer!This is what it says in a copy of a POH, which I have in my possession:
"Throttle settings in cruise:
a) Whilst a moderate throttle setting will ensure the maximum range, an aircraft's speed is one of its main advantages.
b) When calculating the required throttle settings for a journey, the pilot will take into account the meteorological conditions and his/her own capabilities.
NOTE: When flown within limits there is no mechanical reason for not setting the throttle for a fast cruise."
So, why, why not?
1. Faster mean more fuel burn. Moderate means greater range.
2. School FIs can recommend settings like 2200 or 2300rpm. I wouldn't redline the throttle (ona fixed-pitch prop). 100rpm off for a fast cruise would be mechanically okay in the case of the a/c above
3. Your human capability of handling a faster speed.
4. Enviromental conditions.
Check the POH for engine handling/cruise tips. You have read the POH, haven't you?
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Interesting topic this!
In my aeroplane (180hp Lyc with fixed pitch prop)
2050 rpm gives me 120mph indicated
2400 rpm gives me 140mph indicated
2600 rpm gives me almost 160 ias
red-line 2700 gives me a gnat's above 165.
My biggest constraint is fuel - I carry 75litres useable - at 2050 I sip a miserely 30lph, at 2600 rpm I gulp 40lpm.
The (no-wind) sums are quite easy - 2050 gives me 2.5 hrs = 300 miles to dry tanks
At 2600 I get 300 miles to dry tanks! I just get drier faster!
Guess that Spain is going to be something like 8 or 9 hrs each way; 130 v 120 equates to an 8% improvement in performance which equals a true time saving.
An 8% performance improvement on an 8 hr trip works out as getting there 40 mins earlier! As you'll need to stop to clear customs, fuel, overnight, etc., those 40 mins really don't make much difference overall at the end of the day.
Nine years ago I took a C182 across Africa and back. It was 30 hrs flying - I was going through the same quandry then as you are now! I ran the engine at max range power setting - I didn't feel that it was being strained or overworked and the couple of hrs that I would have saved in flight time were eaten up by night stops, bureacracy, etc.
Hope that this helps!
Stik
In my aeroplane (180hp Lyc with fixed pitch prop)
2050 rpm gives me 120mph indicated
2400 rpm gives me 140mph indicated
2600 rpm gives me almost 160 ias
red-line 2700 gives me a gnat's above 165.
My biggest constraint is fuel - I carry 75litres useable - at 2050 I sip a miserely 30lph, at 2600 rpm I gulp 40lpm.
The (no-wind) sums are quite easy - 2050 gives me 2.5 hrs = 300 miles to dry tanks
At 2600 I get 300 miles to dry tanks! I just get drier faster!
Guess that Spain is going to be something like 8 or 9 hrs each way; 130 v 120 equates to an 8% improvement in performance which equals a true time saving.
An 8% performance improvement on an 8 hr trip works out as getting there 40 mins earlier! As you'll need to stop to clear customs, fuel, overnight, etc., those 40 mins really don't make much difference overall at the end of the day.
Nine years ago I took a C182 across Africa and back. It was 30 hrs flying - I was going through the same quandry then as you are now! I ran the engine at max range power setting - I didn't feel that it was being strained or overworked and the couple of hrs that I would have saved in flight time were eaten up by night stops, bureacracy, etc.
Hope that this helps!
Stik
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Monocock - Kirstey has been posting here for a while. Apart from an intense dislike of Lydd she doesn't usually post anything too outspoken 
or were you talking about someone else 
Stik's been here even longer... 
or were you talking about someone else Stik's been here even longer...
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I think Monocock is referring to our mutual fear of water - this being the true reason neither of us hold float-plane ratings!
Recall Kirstey being feisty in the past - but assumed* that this was a genuine, if rather poorly thought through question!
*As I keep telling my employees, "Assumption is the Mother of all F@ck Ups"
Stik
Recall Kirstey being feisty in the past - but assumed* that this was a genuine, if rather poorly thought through question!
*As I keep telling my employees, "Assumption is the Mother of all F@ck Ups"
Stik
Official PPRuNe Chaplain
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"Agrarian" is one who studies the soil.
"Agoraphobic" is one who is afraid of open spaces (the "agora" or market-place).
"AerBabe" is the star-sign.
Allegedly.
"Agoraphobic" is one who is afraid of open spaces (the "agora" or market-place).
"AerBabe" is the star-sign.
Allegedly.
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Agora means NOW in Portuguese, hmmm afraid of the present!
Actually afraid that this morning's forecast of rain from the west might preclude both planned aviation and agrarian activities!
Certainly not afraid of Aerbabe!!
Stik
Actually afraid that this morning's forecast of rain from the west might preclude both planned aviation and agrarian activities!
Certainly not afraid of Aerbabe!!
Stik