701 vs Savannah

[pitfield]

I am wrestling with the choice betwen these two aircraft. Some of you undoubtedly wrestled with the same decision, and I'd be very grateful if you'd reply and explain how you reached your final decision. I am not intending to build it myself, so ease of construction is a secondary issue for me. Thanks very much.

 

 

[vk3auu]

The main disadvantage of the 701 is the draggy slats, although the addition of VG's in their place works OK. The Savannah seems to be a bit less draggy with the VG's. If you can get one or the other with a 80 HP Rotax 912, go for it. The 912S is a bit of overkill. My 701 with VG's does 70 knots at 14 litres, used to do 65 knots at 17 litres with slats.

 

David.

 

 

[Flyingphot]

Hi Pitfield and David

 

I disagree with you David, re the 80 HP. I would always recomend the 100 hp 912-ULS for a number of reasons. The extra power will give a cruise of 90 knots at 16.5 lt/hr. Therefore it is more economical over a given distance.

 

The 100 hp also comes standard with a slipper clutch in the gearbox which the 80 hp does not have. (this means in the event of a prop strike - and they can happen - you do not have to strip down the 100hp)

 

The 100hp comes with carb heat but I believe the 80hp does not.

 

To fit out an 80 with carb heat and slipper clutch will make it cost more than a 100.

 

All that said, I believe you can run the 80 on ULP which some prefer over PULP that the 100 must use (or Avgas).

 

All this to make your decision a bit harder - really I hope it all helps.

 

Cheers

 

Bill

 

 

[ianrat]

We have a 701 ready for painting. I have looked at both the Savannah and the 701. They both have some good features, we preferred the 701 for a number of reasons. it has a full flying rudder (the whole rudder turns not just the rear section) this good for slow STOL maneuvering. It has a large window above your head, this has been useful when we had another plan trying to land at the same time as us and he was just above us and he did not see us but we were able to see him through the window.

 

While at Oshkosh this year we had a good look at the new CH750. This is an excellent aircraft. It has many improvement over the 701. It now has adjustable seats (fore and aft) a redesigned baggage area, a different dash with greater visibility and now will accommodate the larger engine configurations. The kit now comes with matching pre drilled holes (like wing sheets to ribs). It is also wider in the cabin area, this is a great plus for the comfort of the pilot and passenger. I would strongly advise you to have a look at the new CH750 on the Zenith site.

 

Ianrat

 

 

[Marty_d]

I agree with Ianrat - I bought the 701 plans about 6 years ago and all the aluminium to scratch build it shortly after.

 

However I went for a fly in a 750 a couple of years ago and was wishing I was building that instead. It's got several advantages over the 701 structurally - it's skinned in 0.020" instead of 0.016" so stiffer skins (only adds a couple of kg), has a full span rear spar on the wings instead of the full ribs and short rear spars between them that the 701 has, and the trailing edges of wing and stabilizer are folded rather than brought together and solid riveted. (I actually changed my stabilizer to the 750 method because it makes more sense and is a neater job).

 

As well, the corners on the fuselage have a rounded extrusion rather than a folded L - angle, so it takes the "boxy" look out of the edges.

 

I won't get into the whole slats/VG's discussion, I'm building with slats because that's what the original design has, but I understand that several builders have gone for VG's instead and had positive experiences. Interesting that Zenith have now released the Cruzer which has new airfoil and no slats, looks more like a Savannah than ever.

 

In relation to the window above the fuselage, excellent for vision, but some builders are of the opinion that the flat roof where it meets the windscreen stalls at a higher speed than the wing (John Gilpin tested it I believe?)

 

One builder in the US changed his to have an airfoil shape above the cabin and said that it's made several improvements including stability on slow approaches and less oil-canning. (see http://www.zenith.aero/group/stolch701/forum/topics/beanie-mod)

 

Anyway whatever you go for, if it's built straight I'm sure you'll be happy with it! Good luck.

 

 

[ianrat]

Just left the Zenth factory and had a chance to fly the CH 750. Few like a dream and much bigger than the CH701. We had a good look over the new CH 750 Cruise while we were there. They are just about ready to ship the first kits out. No slats but the leading edge has been brought out further to compensate for no slats. Flys faster than the standard 750.