J 170 Ground roll

[puddles_7]

Hi Guys

 

Considering purchasing a second hand Jab J170 and running from a farm strip. What length strip is realistic considering the Jabiru website quotes landing roll 168m and take-off roll as 210m. The strip I use is currently 400m. I am looking for answers based on experience.

 

Cheers

 

Puddles_7

 

 

[turboplanner]

Be careful of published figures.

 

I can land a Warrior almost on the length of the piano keys at Moorabbin, but in a 170 it was somewhere between Victoria and the Antarctic

 

(No I just made that up)

 

The three aspects with the 170 are that it gets blown up and down much easier due to less inertia, it lands quite fast, and although it has brakes, they are no match for the Warriors, so you may roll quite fast beyond the stated landing length, especially so if one wing gates caught by a gust and there's a slight deflection in direction so you momentarily need to back off the brakes, straighten up, then reapply them.

 

Take off roll is fine and very predictable, it hauls itself into the air very well because of the high lift wings.

 

 

[turboplanner]

I should have been more specific.

 

The actual ground roll may be accurate if landed at the correct speed but it's getting it to the threshold of the paddock at the correct height and speed that's the difficult part.

 

I've actually seen 170's still airborne 540 metres down a 1000 metre strip quite a number of times.

 

On the next circuit the wind may be calmer and the guy drops it in over the fence, but it's too unpredictable.

 

 

[Chrism]

I have only had about 8hrs in J170's but in my limited experience I support TP's latter point- compared to a J160 they can tend to float along way down the strip once you are S&L, before you touch down. A couple of times at bankstown that translated to a few hundred metres of a 1km runway, so I think you need to take that into account in addition to the ground roll.

 

Good question though.

 

Chris

 

 

[frank marriott]

Might I suggest be " self critical" of your approach and flare speed. As with all aircraft too fast results in float - A small amount of excess speed at flare obviously has more effect on a light A/C then a heavier one.

 

Frank M

 

 

[Guest Jake.f]

.

 

 

[winsor68]

I reckon if you built a new J170 from a kit and put a Rotax upfront from new (and this is not a Jabiru motor knock) the extra 20 hp would turn it into a better aircraft... and then you could fit after market brakes and not be limited by factory flap numbers... or fit the 3300 jab.

 

Just checked the log book and I did my first 12.5 hours in a J170 from a fairly short strip... probably much of the reason why I always reckon it could use more power. There was also talk about being able to add "turbulator" tape to the elevator to improve its feel... and I wonder how a set of Stolspeed turbulators (ala Savanah) would go on the wing?

 

I reckon its an aircraft with a LOT of potential... potentially? I would like to fly one again one day to see how it feels now I have the grand total of 35 odd hours under my belt... lol

 

 

[motzartmerv]

Hi Puddles. Our school operate a 170 from an 800 m strip. At sea level, on the south coast of NSW. 400 meters should be sufficent for it DEPENDING on a few things.

 

The approach path on both ends needs to be clear for at least twice the quoted to distance. The problem as others have said is the float, a moderately experienced pilot should be ok with it in most conditions, but when things get gusty and blowey, above average skills would be required to operate safely from a 400m strip IMHO.

 

But, provided you dont overload it and pay attention to mother nature im sure it would be fine.

 

Cheers

 

 

[turboplanner]

I don't think the roll distance is an issue, which is why I corrected myself. I think getting the touchdown point accurate is.

 

The factors which will change the roll distance like weight, the state of the grass, and ambient temperature can all be calculated before landing if you know them.

 

Winsor in your area, with warm air I would imagine the 170 would not be much of an issue, say less soggy than a 160.

 

In southern cold air where the 160 is precise, the 170 is jumpy.

 

Jake your ground roll is still close enough to the Jab figures, but if you land just 151 metres past the fence, you're going to smack the fence at the other end, and I'm saying I've seen quite a few still flying at the 540 metre mark........140 metres beyond the end of this 400 metre fence without yet touching ground.

 

Any chance of putting a temporary fence section in?

 

 

[puddles_7]

Guys

 

Thanks for all the prompt responses. Not much experience at this end, still learning so I appreciate the benefit of your experience and wisdom. I was doubtful that 400m would be adequate for conditions other than perfect for a Jab. Take-off I think is OK but landing could be an issue. Looks like I will need to re-think what I spend my hard earned dollar on. Do like the Jab though.

 

Thanks

 

Puddles

 

 

[Guest Jake.f]

.

 

 

[frank marriott]

Motz

 

Just for interest what speed do you instruct for approach in J170 and J230's

 

I have my own opinion but not instructing and gained by RAA lincence by a check flight with a CFI on HP only based on my CASA CPL and have changed my approach speed from what was suggested by the CFI at the time [still inside he POH].

 

Far from starting a debate I am interested what speeds are suggested in your training organization.

 

At the same time I am not being critical of the CFI at the time as he sugggested with a new A/C be carefull about zero power too early on a new engine as it might stop.

 

I am aware this post is getting away from Puddles original question but I think it is interresting, to me at least, if it is too far off track then please reply by PM.

 

Frank M 

 

 

[puddles_7]

Frank M

 

Your question is still within the realms of the subject, I am learning in a J170 so any info I can gain from other's experience is good.

 

A little off topic..... where in Townsville are Ultralights based, I am only aware of Woodstock but whenever I have been past it seems to be unoccupied.

 

Cheers

 

Puddles

 

 

[frank marriott]

Puddles

 

I am at Jones Road which is about 6km west of Woodstock along Jones Road [4 Jabs, 1 thruster, 1 Gazelle, 1 Xair]

 

Another group at Montpellier, which is at Ant Hill Plaines closer to town. They have a variety including Trikes, a Carbon Cub, and a Litewing. The Litewing is owned by Ross (Major on this forum)

 

FrankM

 

 

[motzartmerv]

Hi Frank.

 

In the 170 we do the approach at 65kts and 60 over the fence with full flap.

 

The 230 is similar however slowing to 60 kts a bit earlier helps reduce the float and overshooting the touchdown point. If winds are gusty we encourage maintaining 65 all the way into the flair and not holding off as long, the 170 can run out of rudder in a gusty xwind at low speed so an extended holdoff is not the go.

 

cheers

 

 

[Tomo]

Question to the Jab RAA boys here:Do the Jabs have good quality Pilot Operating Handbooks (POHs) that spell out minimum approach speeds with and without flap to achieve specified landing and takeoff performance distances to clear a 50' obstacle in each case. In other words do they have what us boys who were trained GA call "P" charts? The "P" charts would typically have graphs showing the effects of grass short, grass long, hard surface certain % slopes, pressure height, temperature (density height), wind speed and direction etc.

 

I could determine the landing and or takeoff roll of a C150 or a PA28 or any such GA aircraft to a reasonably conservative accurate figure when I knew weight, pressure temperature and wind and surface.The POH figures were based on average pilot ability. If you were better than average you could better the figure ... so you thought ...

 

David

To answer your question David, in short No they don't compared to say the Cessna's, Pipers. Most Recreational aircraft I've flown don't have very comprehensive P charts.

 

Yeah, I'm with Motz, For me with full fuel full load in a J230 I don't like to approach at no less than 65kts (in my experience), lightly loaded 60kts works well. (Always Full Flap)

 

 

[puddles_7]

Frank

 

Thanks for the reply re Townsville and Ultralights. I live 2500Km away but have both my sons in T'ville, I usually manage 3 or 4 visits a year. We intend to retire up there. I have looked at property along the Woodstock-Guru road and noticed several private strips out there too. I have the VNC Maps for Townsville and have been curious about avoiding the flight steps and still stay above the terrain, heading west I guess you are much better off, Anthill Plains could be a challenge though.

 

It is good to know there is plenty of Ultralight activity in the area so if and when we move I can look to make contact. I am currently living in a Dairying area where most properties are around 100Ha so airstrip size is limited, hence my query re the ability of the Jab to get in and out. Anyway, thanks for the input, have a great day

 

regards

 

Puddles

 

 

[facthunter]

Tomo has mentioned the LOAD. You must relate your approach speed to the stall speed which will vary quite a lot from low fuel and ONE small pilot, to landing at near max weight. Your EXCESS speed will have to be dissipated by floating down the strip or forcing it on and braking. The last technique is certainly NOT recommended in a Jabiru. It'll wheelbarrow and you won't have good directional control, or have weight on the mainwheels to have effective braking. As stated , the Jabiru brakes are not much, but you should not be punishing brakes or even relying on them heavily in an Ultralight.

 

If you had a good clear approach so that you could be ASSURED of putting the mainwheels on the ground every time within 60 meters of the approach end, you'd have enough with 400 meters.

 

The larger wing or the light weight in themselves do not cause the plane to float excessively, it is the fact that you are approaching too fast.( for the conditions) In a Jabiru a fast idle speed will make a plane float too because they are quite a clean aircraft. Also they are not a plane that I like flying slow, because if you do get a bit slow they don't have a lot of control authority, so make sure you do a fair bit of practice.( and do a powered approach under these circumstances).. Nev

 

 

[Kyle Communications]

Buy a Savannah...will land and takeoff in under 50 mtrs and land about the same. You can buy factory built ones or build one yourself. This video is a guy landing at his own very very small strip in basically suburbia not far from me here just north of Brisbane the video speaks for itself on how well they do their job...cruise is 90knts

 

Both these pilots are very experienced

 

 

Mark

 

 

[motzartmerv]

90kts cruise?..whats the VNE?

 

 

[Kyle Communications]

VNE 109 knts

 

 

[turboplanner]

If you had a good clear approach so that you could be ASSURED of putting the mainwheels on the ground every time within 60 meters of the approach end, you'd have enough with 400 meters. Nev

Yes you would, but who could assure this with a wing that's just about as efficient as a feather that reacts to every little puff of wind, not to mention being distracted by the moment arm differential.

 

It's a bit like saying if your Aunt had balls she'd be your Uncle.

 

 

[Thirsty]

Geez with that Sav landing on that small strip in the bush - wouldn't want to have an engine failure on takeoff !

 

 

[Guest Pioneer200]

I consider a 500m strip the minimum that i would operate a J160 in, but saying that there are lots of variables, good headwinds for take offs and landing obviously help heaps as does low temps and high air pressure. Given the variables I mentioned above you could probably get away with 400m and maybe less, but if you are useing the strip lots most of the time one of these will be against you. So 500m it is for me, unless GIVEN conditions on the day are ALL favourable.

 

Also strip conditions play a part to, try and accelerate a JAB fast on grass that is damp and longish, pretty tough!!

 

 

[turboplanner]

A 170 is harder to get down than a 160, so another type AC would be a good bet.