Best Gibbo wing for an HKS700e motor
This is my dilemma, I really like Gibbo wings, in pictures they look like they are built like a tank. But every time I muster the courage up to think about buying one (even though Gibbo has a great loyal following), I get a lot of opinions from the people that swear by Northwing (but everyone is entitled to their opinions). I am hoping to make a rational decision here not based on just the opinions. I think Gibbo wings are priced very fairly too (almost 3k less than a Northwing).
So I have two questions for Gibbo wing flyers. I have an HKS 700e motor with a 19 meter strutted Northwing. The other day I was flying near Payette, Idaho and the air was very turbulent so it required some effort on my part to fly.
My question is this what Gibbo wing is best matched to a HKS 700e motor which many say is a little bit stronger than a 503. For the most part I fly by myself, but my dad is moving to Idaho next year and I will be flying him quite frequently and wanted a Wing that can accommodate two 200 pound people. I think my trike (Northwing Navajo) empty weight with the HKS motor is about 540 pounds. Put two 200 pound passengers and now we are looking at 940 pounds. With all that weight and an HKS motor. What Gibbo wing is the best match?
I am not a cross country pilot, I am a patch flyer. But I am looking for a wing that I can fly by myself in strong turbulence (and it doesn't require as much effort as a 19 meter wing) in turbulent air or thermals but which also has the ability of hauling two passengers occasionally with an HKS 700e motor and not overwork the engine (with one or two passengers).
I still love my 19 meter Northwing, it also is a blast to fly in calm conditions. At one time I thought of getting a Gibbo 17 meter RST wing (instead of the more popular 15 meter RST) to give me better ability of hauling two people (a pilot and a passenger). But then I thought, what if the difference is not significant between a 17 meter Gibbo and a 19 meter Northwing? One of my all time favorite wings was an Aeros Stranger (maybe a Stream) (I believe it is 16 meter double surface) I loved the way it handled.
What are you suggestions? Is there anyone by Boise, Idaho or nearby areas that flies Gibbo wings, I sure would like to test fly the wing to get a better feel for it. Please help me out make a good decision here.
Rizzy
Comments
I'm guessing you are underestimating your power. I've flown side by side with Damien - both of us in nearly identical Northwings with 15m Mustangs. His HKS had pretty similar performance to my 582. Why not make a trip down to Gibbo central and take the wing out for a test to get your own opinion?
Hey Riz,
I think when you mentioned test flying the wing-- that is the best way for you to really figure it out for yourself. Lot's of a wing's characteristics are subjective. I would contact Gibbo himself and ask where he's sold wings nearer to you-- then contact that pilot to fly with him/her. You probably won't find a trike of exactly the same horsepower as your HKS700e, but I think you might be able to roughly approximate it by limiting the RPM of a more powerful motor (you could rough estimate the RPM based on the percentage difference of the horsepower, or even better, look at a HP/Torque curves and get a better estimation of what RPMs are comparable to your Max HP & Cruising HP). I think you would likely be most confident with a purchase (or not) based on your own experience.
Most pilots, including myself, haven't personally flown the combination you're looking at so asking others I don't think is going to give you the semi-solid answer you really want. Here's what I think I understand about wings (PLEASE correct me if I don't have it right) and I don't believe that the general principal for delta wings has changed recently (despite the hope that some express that there's been some magical aerodynamic breakthrough in small wings):
All else being equal, larger wings lift more weight. It takes more energy ( bigger thermals or higher horsepower) to get the same lift with a smaller wing. The shape of the airfoil, as far as I know, isn't as big a factor in generating amounts of lift as is square surface area. A fatter airfoil can generate more lift than a low profile airfoil-- does so at slower speeds and typically has a slower stall speed. At higher speeds a high lift airfoil generates increasing drag until thrust is insufficient to push it any faster. A smaller wing / or a lower profile wing generates less lift- it can go faster / but also has to go faster to generate sufficient lift. It will require more thrust. So generally the tiny winged trikes need huge motors and higher speeds to stay in the air (at an equivalent density altitude). It seems like you're looking for a high-lift, smaller (than you have) wing that needs relatively less thrust and fortunately, are not interested in going faster than average (in fact appreciate the coolness of low and slow)- basically giving up thrust, speed & size for the hope that a high lift profile airfoil can adequately lift the large amount of weight you require at the high density altitudes you fly at.
That's a great question!!!
I'm sure there's a 3-D graph of potential combinations that can work (just like the graphed box we learned about for our licenses outlining the safe parameters for weight/loading and CG). The box outlines what is safe, but inside the box of "safe" is an area that defines "sweet" feeling. It's just unclear if you're at the outside of the sweet area given your parameters, or maybe even outside the physically possible area. I know you keep looking for this perfect combination, but it just might not exist (or be produced). As noted above everything's a compromise.
Usually climb rates are documented at max gross weight, sea level and Vy speed (which is often near best L/D). As far as I know, Gibbo doesn't make a specific trike to match his wings, but I'm sure that Gibbo has documented the performance of the wing(s) you're looking at. He had to have tested them on various trikes. What numbers does he quote (in writing) for what set up, at what speeds? Is it anything close to what you're needs are? (For that matter, are Northwing's stats a near match either?) He must at least have some charts he's computed for the theoretical performance. I'm sure he currently has a trike he can put that wing on-- ask him to fly a certain RPM, with two big guys in it and tell you the climb rate (he's near sea level I think-- but you can calculate the expected difference in lift (there are simple rules of thumb to follow-- I'd give my spreadsheet to you, but it looks like I forgot to bring the file with me right now (ask me later, you can plug numbers right in (weight, climb rate, Temp, Altitude, speed, etc) … its easy to calculate though)).
If the numbers seem to possibly work, then ultimately YOU really need to try and test fly the wing (with & without someone in the back) and see if YOU like the way it FEELS to YOU. I know your money is hard earned-- it deserves you doing the homework / test drive. Someone else's opinion will only get you so far and it would suck if you bought the wing and were unhappy.
The only other thing I was thinking was that you wrote about the "empty weight" of your trike. I've said this a bunch of times, but you'd be stunned by the actual weight of your trike when you really add everything up. I was!!! I made a little spreadsheet to add everything up (super easy to do, just an itemized addition column- starting with factory trike weight, wing weight, BRS weight (25lbs I think))- then add all the do-dads (GPS ~ 1lb, small repair kit ~1lb, radio, batteries, your clothes, jacket, boots, gloves, helmets, bottle of water you carry, ties, tie downs, etc, etc, etc). I was floored when I added it all up!!! I was overweight with full gas, XC equipment, warm clothes, my wife and a little bit of clothes for an XC trip- it adds up really quick. (see Lithium Iron battery here for a potential way to drop 12-15lbs !! (huge!!))
What are the relative weights of the wings themselves? I know that one really bitchen factor about the Bionix 15 I switched to (purchased used) was the fact that although the wing was somewhat heavier than the iXcess 15, it ultimately could carry 50 LBS more total !!! That's huge -- I told my wife she didn't have to lose weight to fly with me XC after all ;) (I'm actually the one who could stand to lose some- but it never hurts to let the wife know she can't just let her looks go :) (Ok, maybe when she socks you it hurts a little).
Anyway, in short: Get the numbers from Gibbo and Northwing, make some calculations to account for your parameters (including lower thrust and higher DA (I can help you do that, but I don't warranty my math/formulas)). If the calculations show you're in the ballpark, go test the nearest one to you (and use some calculations to account for expected differences in thrust / etc).
That's my two-cents (in 2000 words) to this question you keep asking ;)
… or what Ken said
Thanks Ken and David,
I want to thank you for taking time to share your opinions. As far as the difference between the two wings (Northwing and Manta) are concerned. For similar size wings, both of them are very close to the specs (about 7 mile difference). So it seems that you are right, test flying the wing would be the best option.
Someone called me yesterday and have a low hour Contour wing for sale...any of you gentleman have any experience with that wing?
Rizzy
No experience - but its not strutted is it?
This one is Strutted.
I would test fly the contour also, I've heard they are pretty slick