Firewall width comparison

[mcrowley]

What is the firewall width comparison of the Savannah S, CH701 and the CH750? I'm wondering if the cowling options are similar. Thanks!

 

 

[rotax618]

From my measurements the 701 and Savannah VG have the same firewall, the Savannah XL and S have the same width firewall but at about 6deg less rake. I have no knowledge of the 750.

 

 

[eightyknots]

From my measurements the 701 and Savannah VG have the same firewall, the Savannah XL and S have the same width firewall but at about 6deg less rake. I have no knowledge of the 750.

Even though the width is the same, it seems that Zenith 701/750/Savannah VG and Savannah XL/S are not going to be interchangeable?

 

The reason why I am asking this is that I am still considering fitting a Viking 130 to the Savannah I want to build. The problem is that the Viking mob only sell Zenith 750 firewall forward kits (well, also SeaRey, etc but that's another story). The engine would come point forward at the wrong angle presumably?

 

 

[rankamateur]

The engine would come point forward at the wrong angle presumably?

Got an angle grinder and a welder?

 

 

[mcrowley]

I'm installing a Corvair engine and I can tell you that the Corvair motor mount for the CH750 does not fit the Savannah S.

 

 

[eightyknots]

I'm installing a Corvair engine and I can tell you that the Corvair motor mount for the CH750 does not fit the Savannah S.

In which way is it different?

 

 

[AllanBendigo]

I will get you the to firewall sizes today and post here

 

The 750 is much larger than the 701

 

 

[Allan CH650CH750]

I will get you the to firewall sizes today and post hereThe 750 is much larger than the 701

See firewall drawings for 750 and 701

 

 

 

[eightyknots]

See firewall drawings for 750 and 701

That's really useful. All we need now is a Savannah S/XL firewall drawing for a full comparison. Does anyone have such a drawing?

 

 

[mcrowley]

My Savannah S

 

 

 

[AllanBendigo]

My Savannah S

Sav. 711 mm. 616 mm

701. 730mm 610 mm

 

750. 898mm. 690 mm

 

Cheers

 

 

[eightyknots]

Sav. 711 mm. 616 mm

701. 730mm 610 mm

 

750. 898mm. 690 mm

 

Cheers

This is a handy way to compare the fire wall sizes. Thank you.

 

Looks can deceive because if you would have asked me I would have given my opinion that the CH701 was the narrowest. I am surprised to see that the Savannah actually has the narrowest fire wall!

 

 

[rotax618]

Which Savannah model did you get that dimension from? I used a CH701 2 stroke engine mount on my Classic Savannah and the bolt holes lined up perfectly, I compared the Savannah firewall with the early 701 drawings and found it to be almost identical.

 

I later tried to fit an XL engine frame but found the angle of firewall to be different, about 6deg less, so the bolt holes were just a bit off centre.

 

 

[mcrowley]

Which Savannah model did you get that dimension from? I used a CH701 2 stroke engine mount on my Classic Savannah and the bolt holes lined up perfectly, I compared the Savannah firewall with the early 701 drawings and found it to be almost identical.I later tried to fit an XL engine frame but found the angle of firewall to be different, about 6deg less, so the bolt holes were just a bit off centre.

My post was from the drawing in my construction manual for the Savannah S, the penciled numbers are from measurements I took myself. In fact, here are a few more measurements, including the degree of "tilt" I took in order have a custom mount designed and fabricated for my Corvair engine.

 

 

[rotax618]

I ultimately had to build a engine frame to fit the Rotax ring mount to the VG Savannah, but the engine mount bolt hole centres on the original 701 and Classic/VG Savannah are identical, both aircraft were designed by the same people. And one is a knockoff of the other.

 

The XL/S Savannahs seem to suffer more nosewheel cracking-damage etc because of the less caster which increases steering/landing loads, it seems the firewall was made more vertical to increase the windscreen rake and make it look faster. As they say an aeroplane is a million compromises all flying in formation.