TO run for a PA28-140

[mkmkmk]

The graph from the PA28 handbook depicting take off runs is pretty poor when compared to that in the Cessna books which give exact figures. I wonder if anyone has calculated or would care to say which figures they would use for TOR (and TOD if available) for say aircraft at 1950lbs, nil wind, ISA etc.

[Final 3 Greens]

mk

I'd would certainly bear in mind that any PA28-140 is no spring chicken and the POH numbers may be optimistic due to hangar rash and engine condition.

I don't have a POH to hand, but from memory (about 8 years ago), a 1950lb 140 with a cruise prop, in still wind took about 325-350M to break ground and about 6-700M to clear 50'.

Not a short field aeroplane.

Don't rely on these numbers.

[jabberwok]

The figures I have for the aircraft at AUW (2150lb) and in standard ISA conditions are:

TOR 1100ft
TOD 2000ft
LD 1440ft

I also have the following figures for a weight of 1950lb:

TOR 895ft
TOD 1625ft
LD 1170ft

Like Finals though I've got this data in old scribblings and I can't verify the origin so treat with extreme care.

I tended to make notes from the actual aircraft manufacturer handbooks only so I think they might be kosher - but I'd be happier if someone else could chip in here to agree/disagree with the values.

[Final 3 Greens]

Interesting point here.....

1950lbs is the MTOW for a PA28-140 with a 140hp engine.

2150lbs is the MTOW for a PA28-140 with a 150hp engine.

Confused?:ooh: Piper did produce both variants.

I have flown both, but my numbers refer to the former.

[mkmkmk]

Its got a 150 engine. 300m TOR at 1950 and 340m at 2150 is what the book states, soo your figures seem reasonably similar. Just trying to confirm whether taking it out of a 500m grass strip seems feasible, should be fine yet the book makes no mention of what reduction in TOR lowering flaps makes!

[IRRenewal]

mk,

Just a few toughts and observations.

Book figures require an aircraft performing (almost) like new and at least average piloting technique. Do your aircraft and you fall in these categories?

The figures in the book apply to a hard surface. Remember to apply the appropriate factors for a grass suface, normally an additional 20 to 30%. The CAA safety sense leaflet regarding aircraft performance can be found here.

If the book makes no mention of taking off with flaps it means that Mr Piper does not approve of using flaps for take off. I you do, and you break the aircraft (or worse), you have not operated your aircraft in accordance with the POH/FM. If you do not operate your aircraft in accordance with the POH/FM both your CofA and your insurance are invalid.

I am not saying it is impossible to operate a Cherokee 140 out of a 500 meter strip (although I wouldn't), but trying to do so at max AUW might be silly.

Cheers

Gerard

[mkmkmk]

True, which is why its below MTOW. 300X1.3X1.3 (safety margin)=507m. It's clear at the end and downhill, oh and called Cromer!

[BEagle]

"If the book makes no mention of taking off with flaps it means that Mr Piper does not approve of using flaps for take off. I you do, and you break the aircraft (or worse), you have not operated your aircraft in accordance with the POH/FM."

I don't think that would wash these days. Piper would have to have issued an AD stating "Take-off shall not be attempted with flaps extended" or similar - and quite clearly they haven't. It depends upon whether your philosophy is "You can do it unless it's forbidden" or whether it's "You can only do it if there's a rule saying that you can".

Although the PA28-140 POH does not include short field performance figures, that for the PA28-161 does and use of partial flap in the -161 allows rotation 10 kts earlier than with zero flap. Adopting a similar technique for the -140 will also facilitate earlier rotation, but no figures are available for reference.

[LondonJ]

I took off a cherokee 140 fully laden from Sandown (fairly bumpy grass strip). It was about 20 degrees and all the calculations showed it to be within limits (with a 1/3 take off run as a safety factor). The field was very bumpy and the aircraft took a long while to accelerate and because it was grass I took off and kept it in ground effect to accelerate. I used one stage of flap (as stated in the POH). However, the stall warner starting buzzing about 50ft above the ground and so I brought the nose down. This brought me fairly close to the ground. Given the situation again I would not have visited that strip with the aircraft in this configuration as it was a little too close to comfort.

The guy who sat next to me was also a PPL and he had agreed my calculations so even with 2 heads on the case you can never be sure.

Leave the biggest safety margin possible is all I can say.

BTW Sandown, great field and nice guys in the tower, lovely crossing the Solent on a clear day, thoroughly recommend it.
:p

[jabberwok]

Your figure of 507m seems about right after factorisation but I thought Cromer was only 493m long.

Pay more attention to the landing distance required though - it will be longer. According to my rough scribbles using that downhill slope and grass adjustment the LD will be in the region of 715m..

It's all a matter of factors though. If they are kind to you and you have a 10kt wind in the downhill direction, cooler temperatures and firm grass the TOR could be down to 350m and the LD to 480m.

Go the other way though and the values can frighten you. Wet grass, hot day and a mere 5kt tailwind could see the TOR go up to 655m and LD to 920m. The factors don't have to change much to produce large variations in your figures.

Be very cautious.

[Final 3 Greens]

mkmkmk

Your decision of course, but mine would be to avoid Cromer in a -140 - too many variables that could bite as others have said.

I'd start to feel comfortable with about 650M available on short dry grass, no slope, in calm air - no calculations behind this, just experience .... but a lot depends on the condition of the airframe and the engine - I used to fly fairly "tired" -140s (and -140s with 150 engines.)

BEagle

You mention the use of partial flaps on a -161, for sake of clarity, IIR that is 2 stages (25 degrees)?

[S-Works]

Crumbs! there is now way I would take a Cherokee into Cromer. I took my Cessna in there during the "summer" and it was marginal for me and I have very good short field perfromance with my modded aircraft.

Cromer has a very marked downhill slope especially at the end and is not the bext of surfaces, aircraft are slow to accelerate and slow to unstick.

I flew a 140 out of Sywell a couple of weeks ago and on 03 the long runway we struggled to clear the trees, 2 up and half fuel and that runway is 900m.

[mkmkmk]

I may bin the idea and find another seaside airfield for the weekend! I took it out of North Coates at similar weight and reckon I was off somewhere between the halfway point and two thirds of their 650m. Clacton at 600m might not get my pulse rate as high!

[BEagle]

Well, I had to recover a PA28-140 from a field recently. Assuming 'short dry grass', the figures I got for TOGR at the weight I estimated were as follows:

+15degC/15kts headwind: 285m
+10degC/10kts headwind: 267m
+15degC/still air : 330m

Note how significant the temperature change is!

I had about 380m available (max) for take-off ground roll; in the end acceleration wasn't as good as I'd anticipated and acceleration in ground effect was only possible across the downslope by making a cautious turn immediately after unstick.

If you're going to use a PA28-140 on a short strip, you should define yourself a 'reject here' point where you will assess the IAS achieved against TOGR. Also, be as light as possible and know how to do a soft field take-off.

If I recall correctly, the short field figures in the PA28-161 do indeed assume 25 deg flap (two clicks).

[Final 3 Greens]

Hi BEags

Some of the -140s that I flew were fitted with "cruise optimised" props, they were aways reluctant to accelerate.

God only knows what efficiency they delivered on the take off roll, especially in the early stages :mad:

Perhaps it's no wonder that some of the little darlings don't want to accelerate?