After 3 years of flying without the VGs, I added them to my MX7-180C. I haven't changed my approach speeds (I fly short final at 55 for short strips, and 60 for strips > 1,200') but the plane is a lot less "mushy" at 55 than it was without the VGs. I wasn't shopping for any new capability, I was shopping for a wider margin for error. The level of control feel for the way I fly is greatly improved. I have no regrets for the investment.

onfinal wrote: ↑

Sun Jan 31, 2021 8:30 am

Hi Rezrider,
A couple of YouTube links on VGs. (I apologise if you have already seen them).
Both are as 'scientific' as you can get in a SEP without carrying an academic with 3 ton of measuring equipment in the backseat.
On a Supercub - USA-35B airfoil
https://www.youtube.com/watch?v=aXS0nF1ILns
On a Bearhawk - Ribblet airfoil
https://www.youtube.com/watch?v=7I_ac9Wek-k
Sorry, can't find one for Maules - modified USA-35B airfoil.

Interestingly both reviewers mention about also placing VGs on the elevator underside to maintain attachment of that airflow.
I find the main benefit is improved control authority at slow speed, both in level flight and banking.
I have VGs on the wings and underside of the horizontal stabilisers, along with the gap seals.

I can vouch they improve her smell as well.

Great info, thanks.

Rez,
In my opinion it is the best improvement for the Maule. On my M6, it went from one wing or the other breaking hard and the plane going into a spin. With the VGs all it does is a very gentle mush with power on. With power off it will not stall. I also noticed the better control at slow speeds, especially on landing. I think the safety from the lack of a nasty stall is worth every penny.

I have no experience with VGs on any of the planes I've owned. I've been thinking about them for my M5. What is everyone's experience with cruise speeds? My family and I will be using the Maule to travel quite a bit, and I really don't want to loose any cruise speed.

You may see a very slight loss of top end. But you could probably gain it back by cleaning up some other fairings. We’re talking 1-2mph

The drag from my 31" ABW tundra tires vastly overwhelms any loss of airspeed that might be due to the drag caused by the vortex generators. I would say that even the drag from unfaired gear legs would overwhelm it.

VGs make a Maule a Maule. Can't imagine one without them.

andy wrote: ↑

Tue Feb 02, 2021 2:45 am

The drag from my 31" ABW tundra tires vastly overwhelms any loss of airspeed that might be due to the drag caused by the vortex generators. I would say that even the drag from unfaired gear legs would overwhelm it.

This is exceptionally true.

I am curious if you and others have elevator Gap seals as well.

I have the VG on my M7 but no gap seals. I am wondering if they is even more benefit once you have VG's

I do not have gap seals. I am just losing elevator when I’m going tail low landing with stock length HD gear and 31” mains. That said a touch of power sure makes it feel like I could do a loop from a flare. I suspect gap seals would reduce or eliminate that burst of power I use. I think both VG’s and gaps can seriously change the stol game of a Maule but VG’s likely have the most dramatic effect and gaps really just enhance the experience. But I really couldn’t say personally.

My plane has VGs and when I got it it had ratty cracked gap seals. The elevator and horizontal stab were not connected, gap seal was flapping in the wind hanging from the stab. I flew like this for 20 hours.

I put new seals on and there was a noticeable difference in elevator authority immediately. It’s almost “sensitive” in the flare, before it was very mushy. I was surprised, honestly I only got new ones because Andy young saw it and said “you need new elevator gap seals”. For $100 and 10 minutes of labor (assuming you don’t have to remove old ones), it seems like a good deal.

Elevator gap seals are very helpful in improving elevator effectiveness at low airspeeds. Maules have heavy tails that tend to droop at slow airspeeds. The elevators have to work harder to overcome the weight. Air rushing through the gap between the elevator and horizontal stabilizer reduces the pressure that makes the elevators effective. The reduction in pressure is most evident at slow airspeeds and makes it harder to raise the tail to avoid a bounce in a slow-speed wheel landing.

andy wrote: ↑

Wed Feb 03, 2021 5:07 am

Elevator gap seals are very helpful in improving elevator effectiveness at low airspeeds. Maules have heavy tails that tend to droop at slow airspeeds. The elevators have to work harder to overcome the weight. Air rushing through the gap between the elevator and horizontal stabilizer reduces the pressure that makes the elevators effective. The reduction in pressure is most evident at slow airspeeds and makes it harder to raise the tail to avoid a bounce in a slow-speed wheel landing.

Well then, maybe I don’t need them as much as I thought. I never wheel land.

The heavy tail makes it natural for a Maule to land 3-point. Some Maule pilots touch down first on the tail wheel to feel for the surface and then execute a "double-thump" 3-point landing.

I started doing tail-low wheel landings all the time in 2012 when I flew a Super Cub in the Idaho back country and later in 2016 when returned to fly them in my Maule with 31" ABW tundra tires. The airstrips in the back country were so rough that I was worried about damage to the tail wheel or tail spring so I kept the tail off the ground as long as possible on landing. It also made it much easier to see what was ahead of me over the glare shield: deer, moose, bear, people, other airplanes, rapidly approaching trees and terrain, etc. I don't generally use brakes with the tail off the ground because of the risk of a nose-over. On a short airstrip (< 800') where I need to use the brakes, I do a 3-pointer.

Because the big tires make it more difficult for me to see over the glare shield, I use wheel landings even on longer airstrips now. Most of the time I'm landing on bumpy grass to avoid wearing out the tundra tires. On a bumpy surface I think it's still a good idea to keep the tail in the air as long as possible. The tail spring bracket bolts will loosen up and wear over time if it bounces a lot. It's a good idea to check them for tension and wear at each annual.

To be clear, I land tail low and then end up tail high on roll out. I do not consider this a wheel landing as it’s done at much slower speeds than is possible in a true wheel landing. My raised tail is typically due to heavy braking more than elevator.