Replies to This Discussion

Permalink Reply by Normand Lambert on January 14, 2015 at 11:12pm

Hi Jerry,

I also have a CH701 without Slats but with VGs installed on main wing. CG calculations didn't make that much of a difference with or without the Slats. I used the leading edge of the wing instead of the leading edge of the Slats.

The only difference is for the actual CG range; you can't use the range (in inches) provided when the Slats are on the wing.

Instead, use the percentages of the wing chord to calculate the new CG range 20% to 35% of MAC.

For the unmodified CH701, the MAC is the Chord(Slat + Wing + Flap); for yours and mine the MAC=Chord(Wing + Flap).

The normal chord is 56 inches.

I would say there is almost 6 inches difference with/without Slats. When I go back to the airport, I'll take the exact measure for the Chord without the Slats.

Regards,

Norm

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Permalink Reply by david shrader on January 15, 2015 at 3:08am

I did the exact same as Norm. Leading edge of wing

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Permalink Reply by Jerry Pommerenke on January 15, 2015 at 9:51am

Thanks Norm!

Just the info I needed!   I can measure the chord without slats on our own aircraft - what I thought I could use is the chord measurement with the slats on?

I, nor my partner, have yet to fly the aircraft yet as we are still going over it with a "fine tooth comb" (we have had it for about a week).   The previous owner had finished 31 of the 40 hour phase one testing.   His documentation of those 31 hours is locked up in his brain somewhere in a hard drive that no longer seems retrievable!   This is probably OK since, being as we have no experience in a CH701, or a local instructor with any LSA experience, we should start from ground zero with our own phase one testing.

My previous experience is in Piper 28's and Cessna 172 - my partner has about 100 hours in his own Bellanca Super Viking.   We both have been searching online for articles on any "unique" flying characteristics of the CH 701.   If you have the time, we would very much appreciate any input that you might have in this regard.

Thanks again,

Jerry

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Permalink Reply by Normand Lambert on January 15, 2015 at 12:19pm

Hi Jerry,

No problem. See my report on flying the 701 on this site. Lots of info that is really pertinent because we seem to have the same configuration for our planes.

Check Normand Lambert and look at my discussions. The 701 is NOT hard to fly BUT you have to fly the plane down to the ground with some (1/3) engine power for the first few hours. DO NOT use the flaps for the first landings (not really needed anyway) because they slowdonn - STALL the plane if not carefull.

The CH701 is REALLY HARD to STALL...It kind of mushes around but stays controllable (sink rate 1000ft/min). As soon as you push the nose down, it starts to fly again... Too easy and FUN !

Otherwise, fly the CH701 with rudder/ailerons for coordinated turns and ...ENJOY !

Have any question, just ask !

Regards,

Norm

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Permalink Reply by Jerry Pommerenke on January 15, 2015 at 4:10pm

Norm:

I asked Zenith the same question regarding the datum line for a CH 701 without slats.  Here was their answer:

I guess my next question would be "what are you (Norm) using for CG limits?".

Hi Jerry,

It's 158 mm between the slat and the leading edge but I'm not sure that is really going to be as much help as you think. The CG limits are based on the slats being installed. Removing the slats reduces the wing chord and area which affects the CG limits. We don't have a problem with people flying them without the slats but they are venturing further in the "experimental" side as we don't have published CG limits for the aircraft without slats.

Caleb Gebhardt

Zenith Aircraft Co.
(573) 581-9000
caleb@zenithair.com

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Permalink Reply by Normand Lambert on January 17, 2015 at 10:11am

Hi Jerry,

Do you have the measure for the chord of the wing without the Slats ? To get it, measure the distance between the flap trailing edge to the wing leading edge(nose). CG range should be 20% to 35% of that distance from the leading edge of the wing. I'll go to the airport on sunday (evening) and measure my chord and let you know where that stands. I also will look up my CG calculations paperwork but know this : I removed the Slats and supports and didnt see much of a difference in flight characteristics. Since my plane was on the nose heavy side and the Slats are close to the CG, that actually helped !

I'll check and let you know,

Regards,

Norm

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Permalink Reply by Joe Spencer on January 18, 2015 at 7:51am

I didn't really get too much into the paperwork on mine but instead started gradually loading it more aft and see how it did. got up to 40# in the bag compartment with full fuel and Rockie in the right seat and it flew fine so went with that. Based on that I don't see a way to get mine outa limits aft(or forward for that matter) with any of my loads as long as the 40# bag limit is honored. So my preflight paperwork is "pretty simple".

That covered what Caleb is talking about for me.

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Permalink Reply by Normand Lambert on January 19, 2015 at 12:14pm

Hi Again Jerry,

So I went back to the airport and measured the wing chord without the Slats. With the Slats 57inches, without the Slats 51 inches and 6 inches = 154mm which is almost identical to Caleb's calculated distance...

Now, this means that :

With Slats : Forward range 57in x 20% = 12 inches

                  Rearward range 57in x 35% = 20 inches

WithOUT Slats : Forward range 51in x 20% = 10 inches

                         Rearward range 51in x 35% = 18 inches

So, as you can see there is not much difference between the two configuration and since you're never limit forward/rearward you are still OK.

I found my calculations and here is what I got

CG with Slats ; plane empty : 12 inches

                       plane/pilot/copilot (no bagage) : 16 inches

                       plane/pilot/copilot/50lbs bag : 17.5 inches

CG withOUT Slats ; plane empty : 7 inches

                       plane/pilot/copilot (no bagage) : 10,5 inches

                       plane/pilot/copilot/50lbs bag : 11.5 inches

So, It is still all good. In fact, the CH701 flies better now than before.

Regards,

Norm

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Permalink Reply by Jerry Pommerenke on January 19, 2015 at 1:57pm

THANKS AGAIN NORM:

You have made life a lot better down here!

My new issue is that in order to register the airplane in Minnesota, we have to show proof of insurance.   The EAA insurance people say each pilot (me and co-owner) must have two hours of instruction/orientation for them to insure us.  My local instructors declined based on there having no knowledge/experience with LSA, STOL, or Zenith.   In lieu of an instructor they will allow another experienced CH701 owner to do the orientation.  That person doing the orientation does not have to sign off on anything as we, as owner/pilots,  just enter in our own personal log books the time and whom we received the orientation from.

Any chance you might be visiting central Minnesota soon for some CH701 orientation?  :-)

I, again, can't begin to thank you enough for all of your time and the willingness to share your vast experience about the CH701!

Jerry

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Permalink Reply by Robert R. Kissell on January 19, 2015 at 4:13pm

Hi Jerry,

What engine do you have in this aircraft and what is the empty weight? My experience is with slats and thus the flight characteristics would be a little different than mine. My 701 is light and has a 100HP Rotax which makes it peppy.  It tends to transition to a controlled sink rate ( space shuttle rates)  rather than a conventional stall and break. Which is great for short field approaches, with out slats I have read you will get more float and less sink so approach would be more conventional. The biggest discovery for me was low inertia,  the 701 will speed up quickly and more importantly slow down quickly into a sink. Plan ahead and drive to the ground for awhile until you get a good feel for the loss of speed when the power comes back. And use of flaps are in general not required or recommended until you have some significant hours driving it.

Inspect the stabilizer mounting brackets, some of the early ones would crack, Zenith went to a thicker material to solve that. Also inspect the engine cooling hose routing to make sure that when under pressure they do not (can not) touch any part of the hot exhaust. I could go on for hours..about this bird.

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Permalink Reply by Normand Lambert on January 19, 2015 at 10:23pm

Hi Jerry,

Not a problem, always keen on helping other CH7xx owners/pilots. As far as passing thru Minnesota for some flight time...I would REALLY LIKE that but I'm not planning any such thing for awhile. If I were, I would be more than willing to help.

Actually, I'm supposed to test fly a CH701 that has been reconstructed/remotorized. That should happen in the next few weeks...We'll see about that. I test flew mine (scratched built) and found it easy to Takeoff/fly. My experience is with the common C150/152, C172. Then transitionned to PA-28-160 Cherokee and then ...the CH701. I read a lot about the flight envelop of the CH701 before actually flying it. What I found was that lots of incidents happened on landings. Pilots left the speed bleed off too high/too soon which resulted in a mush down the runway and a bent nosegear/maingear.

So, for the first 20hours I greased in the CH701 with 1/3 power. Never had a problem. Very docile bird. The second thing I wasn't aware of is that you have to use rudder/ailerons in turns; I was told all slower planes are piloted this way.

My 200 hours on the Cherokee didn't help me there : the Cherokee doesn't need much rudder input inflight...

Nevertheless, you get used to this rather quickly and it becomes a second nature... Much like piloting a Cub.

I would suggest you get the Vortex Generators for the elevator and for the main wing they help A LOT with the slow speeds during landings. With those, the CH701 becomes almost a C150 like bird...

Finally, get some photos of your bird, lets see them on this site ! ALways nice to see other CH7xx...

You need more infos keep asking, it's FREE!

Regards,

Norm

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Permalink Reply by Ron Crook on September 12, 2017 at 7:11am

Can u tell me if the measurement slat to wing is still 16mm at the top space and 110 at the bottom thanks ronflys701@hotmail.com. Someone said it was changed?

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