I have made several flights on my zero time new plane , it is very evident that certain mods are benificial, first flight ,2500 msl , 5800 rpm 101.27 mph no wind, plane has streamline struts , horizontal stabs.beenie mod, stall fences, ring mount and tuned intake on 912s , considerably faster then my other 2- 701's what have others experienced ? I know some mods have no pay back , I am not interested in speed with a 701 , only fuel economy that comes with a cleaner plane without loosing performance, such as slat removal 

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stolspeed.com their R&D reports claim 23% fuel savings without slats.

I have spoken to several people that say they cannot tell the difference with takeoff performance since they also report no change in trim with the same stall speed. I believe they are being honest with me. it seems that there are two camps in this regard. those that have tried VG's and those that have not. which are you?

I plan on at least trying when my airplane is born.

What is your WOT RPM? What is your WOT speed? I have a different engine & this is my way of comparing.


Ivan in Texas

the rotax limit is 5800 for 5 minutes, the faster you go the higher the rpm  CAN   climb , im sure in a flat level flight I could reach the 6000 red line , at 5800 the 912s motor makes 100 hp and if pitched for that then you are using 100hp.. my WOT is set for 5800 by prop pitch, and my no wind speed was 101.27 true ground speed ,backed off to 5600 max cruise was 90+whats to compare, what does your GPS say for ground speed allowing for wind 

I have tried both ways and slats are for SHORT take off performance, removal gives you about 3-4 mph speed increase, but if you want a fast plane dont build a 701 build a 601, if I had the money I would buy a HELO currier and I would definately not remove the slats from a 1.5 million dollar plane and try to tell all that I made an improvement. its total BS

Hi Bob,

Losing the SLATS was one of the best mods for enhanced speed...Almost 10mph gain right there ! Installed VGs on main wing didn't adversely modify high speed. Beanie mostly a LOW SPEED benefit for the 701 (and pilot!!).

I also installed streamlined struts from day ONE, so don't really know what difference it made. I can tell you that I flew

with another 701 (stock) and I could tell I was somewhat faster without being at WOT...

I see you are on skis, these speed readings will change with the tires because they drag so much more.

Same speed with power setting lower = fuel economy !

Enjoy your new bird!


thanks Norm, I  only use ski's and floats , this is my third 701 , and first with the ring mount, I would like to make fairings for the struts next ?? , and you are definately right about the fuel economy ,this plane has the origional 5.5 gallon tanks as reserves , outboard of mains, important to carry fuel here in Alaska , 

Hi Bob, Rusty here building my CH701 in Washington state. Have the tail section complete and I'm currently working on the wings. I was wondering about the stall fences you mentioned and how they help? Also I would like to know more about this "tuned intake" system that you spoke of. I thought that was the standard intake that came with my Fire Wall Forward package. Any advice?
Thanks Rusty

Rusty, the firewall forward package uses the 912s motor but has KN air cleaners  hooked to the back of the carbs , the 912s motor at BEST will make about 91-92 hp without the tuned intake , depending on under hood temps and under cowl positive air pressure, the hp gain according to the Austria factory is from the ability to controll these factors , also ram air from outside the cowl , AND the undisturbed air supplied to the carbs , many engineering things that I dont fully understand , velocitys etc. the stall fences keep air from sliding off the wings, direct air flow and generally increase slow speed handling , as do horizontal stabs on the elevator/horizontal tail.BOB   

Bob, where can I buy the "tuned air intake" box, and also the stall fences?? Or are there plans to make the stall fence? Thanks, Rusty

The tuned intake is a Rotax part  , LOCKWOOD, ZENITH or, sometimes on internet, new/used , the stall fences and horizontal stabilizers you make out of .024 I have 3 per wing each 1 1/2" high ,horiz. stabs are same size..1 1/2" and contour of horiz.tail from around  front edge to elev.hinge pin ..BOB


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