Thank you for the information, I am a ways out of needing an engine but want to do some research to find an engine that will work for the 750 and not cost more then the plane. Any input you have will be appreciated. I also like your modified wing design and plan to use it on the plane rather than the slats. Thank you again for your response.
I checked the photos...Ok for the elevator. I went to the Savannah website and checked their VGs on wings. They are all spaced equally for the entire wing...I guess that if you wanted the wing to stall inboard first you would want to have more VGs (spaced closer) near the wingtip compared to the ones installed near the cabin...
Since the 701 has washout at the tip and flaps are somewhat down (compared to the ailerons), our wings will always stall from the cabin outward to the tip, we can also use the equal spacing for the wing VGs. The 701 wingtip and aileron should continue to stall last thus retaining full attitude control.
Still pondering... and with the weather being so-so, not yet ready to install.
If you were to put 1 Vg every 60mm (6cm) you would need 5 per foot X 12 feet per wing = 60 per wing (120 for 2 wings) !!!
The wing kit only has 46 aluminum VGs... If I wanted to put them at equal distance, I would have to put them 6 inches apart for the whole wing... (23 per wing = 1 every 6 inches)...
I understand that if you wanted the center part of the wing to stall first, you would put the wingtip VGs closer together than the ones near the wing root... But how close and is it needed for our CH701s?
That's where I took the info but the placement is for their PLASTIC VGs and mine are like yours Aluminum...So, I'm still trying to figure out the spacing. The placement on the wing is OK but the different spacing (outboard/inboard) is still being debated...
Hi Ron the weight and ballence came to 735 lbs and I am at the forward limit at 11 .5inches empty .personally I would like to move my battery back to the back of the plane as I think the forward limit doesn't work well for the solo ops and I don't think I can add enough weight to the plane to reach the rear limit at 1200 lbs gross so I think I will just move my battery back and I think it will fly better not that there's anything wrong with wats the set up now I just think that it will make slow flight landing even easier all good thanks Jim. When are you going to be flying
Hi Ron yes it was worth the wider cabin ,I flew a stock 701 for a few days with two people on board before I got my papers and it flys the same but it feels like a much larger plane in fact I had mine and the stock 701 side by side and every one was commenting on how much bigger mine looked also because I made the gear 3 inches longer and mine has larger tundra tires but the flight characteristics feel the same .very very happy with it .thanks Jim
Ron you are correct I know nothing about the particular Porche version of the VW engine you are building. I do have several friends that drive Porche, and if the engine you are using is out of the 944 then I can also tell you the 944 suffered a catastrophic failure at 45,000 km when the timing belt failed (belt was 10 yrs old). I did not intend to offend you by my comment, I was only wondering if you were aware of other builders efforts with VW engine conversions. I have some first hand experiences with Subaru conversions in both the CH601HD & CH701 airframes, and none of it has been good. I'm sorry if my comment upset you. Enjoy you build.
Wayne Clagg has installed a Rotax 912S engine in his CH701. He "invested" over $10,000 in machining, and time trying to make the VW work as an aircraft engine. He might be worth talking to before you travel the same road. Just a thought.?
I just found out a few minutes ago. I am just devastated. We had talked a few times about his issues but he preferred to not discuss it, he wanted to talk Vw's to keep his mind off it. I really, really, just don't what to say. What a loss. Wayne
Hi Ron, yes you are right about other people not knowing much about engines. I am satisfied with my test results, confident that the fat fin mod is a huge help. The original test heads were used, at times being up to 500 degress around the plug hole. I wanted to try the experiment on a disposable set of heads for obvious reasons. After 11 hours I had a crack develop between the valve seats on munber two cylinder but all the other cylinders were perfect and required NO valve adjustments for the entire time. I am confident the crack is a result of the heads having been cooked for 60 hours before I modified them. The exhaust valve on number required adjustment from the start of the fat fin test, every 1.5 to 2 hours run time. I have two hours on the new heads and when I checked the stud torque and valve adjustment I found them both to be good. Stay tuned.Wayne
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