those are some mighty big claims they are making. Cant wait to get your report.

That’s fine and it’s nice to look at but it really says nothing. It’s reminds me of the Tamarack winglet; if the strakes are that helpful, the 421 doesn’t have enough power or wing for that regime. Entirely possible. Strakes can be really effective at adding lift to the plane. But they look almost vertical on the 421 application. Look at a Lear and you can see where they would add lift at relatively high AOA.

Anyway, seems like there is no reason there isn’t published data other than it doesn’t really work as good as the marketing. IMHO of course. Even more so with hub caps. You could take those off and on on the same day easy and do back to back flights with some semblance of an experiment.

Anyone know of a good TransAtlantic Ferry pilot with lots of 421 experience? I want to bring a 421 to Utah from Germany.

Mike

+1 For the hubcaps. You will see a difference!

Max's observations may be a bit anecdotal, but they can't be completely ignored. He clearly observed a change in performance with the strakes. I don't get the feeling he's making a commission on strake sales.

The hubcap performance is probably somewhat overrated...I'm sure there's benefit, likely not as much as they claim...but for the price, who cares.

IMO the mod that improves a 421 more than any other is the wing extension (sold as winglets). Essentially the 414A wingspan on the 421.

"Our Cessna 405 series III Speed Covers offer fuel savings 5-10%. Horizontal distance flown reduced by 18% with an increased rate of 25% on climb. Extra lift, reduced drag, lower angle of attack in climb, cruise and descent."

Sounds like it reduces range by 18% while saving 10% on fuel. Weird.

If you like the way they look, go for it. If you want 10% fuel savings, you are looking in the wrong place.

Mike C.

The easy test for hubcaps is install just one and see the rudder required

Worse part of this graph is the stock 421 is under 400fpm from FL200 to FL2500? that can't be true? Man that's worse than my Mirage.

Mike

Worse part of this graph is the stock 421 is under 400fpm from FL200 to FL2500? that can't be true? Man that's worse than my Mirage.

It's been several years since I sold my 421C, but she really wheezed above FL200. I think I only climbed to FL250 once because the last few thousand feet were so painfully slow.

"Our Cessna 405 series III Speed Covers offer fuel savings 5-10%. Horizontal distance flown reduced by 18% with an increased rate of 25% on climb. Extra lift, reduced drag, lower angle of attack in climb, cruise and descent."

Sounds like it reduces range by 18% while saving 10% on fuel. Weird.

I put hubcaps on my 414A several years ago and they worked as advertised. They really helped with climb and high altitude cruise speeds.

I recently put them on my 425 but they don't seem to make any noticeable difference. Why is that?

On my 421C, they helped at the highest AOAs the most. That made for a significant improvement in the 20s where the pistons really struggle for altitude. The 425 doesn't have that issue.

Just an educated guess.

Worse part of this graph is the stock 421 is under 400fpm from FL200 to FL2500? that can't be true? Man that's worse than my Mirage.

Mike

Jason

Surprised by the low climb rates. But I think at 140 and lower power settings that makes sense.

When you could not climb thru the ice did you have full power? I personally would have wanted to get thru and on top ASAP. Climbing thru ice scares the heck out of me. In the PA-46 ice penetration speed is above 130 and even at full power the Mirage would not do well at all once it got a little ice on it.

Here is the page from the 421 POH about cruise climb and full
Climb power.

Mike

The POH suggests you weren't configuring it for good climb rates.

See the climb chart (1976 421C):

The red lines represent the following altitudes:

0 MSL - 1950 FPM
10K MSL - 1550 FPM
20K MSL - 1200 FPM

This assumes ISA and gross weight (7450 lbs). Climb speed is 111 KIAS to 20K. So using max power and best climb speed seems to make a very big difference.

The cruise climb chart uses 1900 RPM and 32.5 MAP and 120 KIAS and achieves:

0 MSL - 1220 FPM
10K MSL - 960 FPM
20K MSL - 720 FPM

If a 421C is realistically a 500 FPM plane above 10K MSL, I am sure glad I didn't buy one.

Mike C.