At home on the Ice here in NWT! '90 Christen A-1

[belloypilot]

Befor we discuss speeds again, check the accuracy of the statip ports by the described procedure. Set Altimeter to an even indication on takeoff, do an low pass over the takeoff oposition, then read the altitiude, it should be slightly higher that when sitting on the ground.

Good point. I’ve followed your advice and I think I have that sorted out. I had the corrupt static issue. I don’t have a ‘pinky ring’ but I think I have it as close to accurate as I can reasonably get with an o-ring and electric tape fix. After a lot of testing I’m pretty confident of my cruise speed TAS numbers now.

 

[tbienz]

Just run a GPS triangle at cruise if you want real numbers. IAS is always "wrong" unless everything is set up perfect and you are at sea level. I have two "very fancy" air data computers in the Mitsubishi and sometimes even they don't fully agree on how fast the plane is going when reporting TAS. Your travel over the ground in three directions on a relatively calm wind day will answer your questions.

 

[belloypilot]

Just run a GPS triangle at cruise if you want real numbers. IAS is always "wrong" unless everything is set up perfect and you are at sea level. I have two "very fancy" air data computers in the Mitsubishi and sometimes even they don't fully agree on how fast the plane is going when reporting TAS. Your travel over the ground in three directions on a relatively calm wind day will answer your questions.

Yes, that’s how I check TAS.

 

[RamBuster]

RamBuster, keep in mind that the PowerFlow exhaust comes with some issues. Take a look at the following threads: https://flyhusky.com/forum/index.php?threads/powerflow-exhaust-cracks.2884/#post-29460

I ended up going back to the stock exhaust for the following reasons:
1. The PowerFlow design/construction is prone to cracking
2. At every annual, the exhaust system is required to be removed from the engine, then the individual header tubes removed to clean the slip joints. It is not a huge job by any means, but is just a little more work every year that does little to solve the PowerFlow's cracking problem.
3. The factory blames the cracking problem on engine vibration; however, contrary to what the factory says, engines that are dynamically balanced still have the problems with the PowerFlow cracking.
4. The PowerFlow exhaust weighs a bit more than the stock system.

If you really need more cabin heat than the stock muffler can be configured to put out more heat, take a look at https://flyhusky.com/forum/index.ph...ailblazer-2-blade-composite-prop.1536/page-12 posts #208 through #221

Thanks for the info on this! Good to get both sides of the picture on the powerflow. This forum has been great to pick up some tips and tricks, this heater improvement is going to be an important one!

Cheers,

Mason

 

[Ak Kurt]

Some Powerflow units have cracked, mine included. The Powerflow cracks I experienced were nothing compared to the cracks I experienced on my stock system. The Powerflow cracks were repairable and so far my repairs are holding. My stock unit almost lost the tail pipe off the muffler, it was barely hanging on. The stock unit produced poor cabin heat. Even with the easily repaired cracks on my Powerflow I think its a superior system compared to the stock system when it comes to durability. The performance increase was no where near what Powerflow markets but there was a slight increase. The increased cabin heat output was a BIG plus! So in my experience, although not perfect, warts and all, I find the Powerflow system better overall to the stock system. Now, that being said, I have no idea how long the system will last, it may turn out to be trash down the road which I doubt but could happen, I dont know, but what I do know, a lot of stock systems are cracking and not repairable.

Kurt

PS, I should say that Aviat has indicated they have addressed the issues with their vendor on their systems and hopefully there will be no further issues. I sure hope so. If true and if the Powerflow gives me any more trouble I will switch back but only if the new stock systems cracking issues have been solved.

 

[flyingjack]

Some Powerflow units have cracked, mine included. The Powerflow cracks I experienced were nothing compared to the cracks I experienced on my stock system. The Powerflow cracks were repairable and so far my repairs are holding. My stock unit almost lost the tail pipe off the muffler, it was barely hanging on. The stock unit produced poor cabin heat. Even with the easily repaired cracks on my Powerflow I think its a superior system compared to the stock system when it comes to durability. The performance increase was no where near what Powerflow markets but there was a slight increase. The increased cabin heat output was a BIG plus! So in my experience, although not perfect, warts and all, I find the Powerflow system better overall to the stock system. Now, that being said, I have no idea how long the system will last, it may turn out to be trash down the road which I doubt but could happen, I dont know, but what I do know, a lot of stock systems are cracking and not repairable.

Kurt

PS, I should say that Aviat has indicated they have addressed the issues with their vendor on their systems and hopefully there will be no further issues. I sure hope so. If true and if the Powerflow gives me any more trouble I will switch back but only if the new stock systems cracking issues have been solved.

Kurt, were there specific years with the stock exhaust issues? In nearly 3 yrs (07 A1-B 1550TT) we've put on nearly 400 hours; very few on smooth RWs (solid or grass) and haven't had any issues. Also, front vent gets almost too hot to touch but hasn't melted plastic eyeball vent. Back seat gets good heat as well. I've check muffler and exhaust several times since reading your info but found nothing, yet.
Jack

 

[Flying Dave]

Anyone ever looked at the floor under the heater box after installing the PF? Granted our airplane has more time than most but the floor looks pretty rough under ours from the heat (stock exhaust) to the point I feel it could use some sort of insulation. Can’t imagine what even more heat must do to it over time.

 

[dogday]

My 2001 A1B had 2000 hrs on the exhaust system without any log book entries showing that the system was ever repaired. I bought the plane at auction from the Department of Interior and all of the repair records over the life of the plane were meticulously kept. HOWEVER, I can't be sure that the exhaust system wasn't repaired at some time during the initial ~2000 hours because the aircraft was used in Northern Alaska and at some point, someone made an undocumented modification to the muffler shroud similar to what is described here: https://flyhusky.com/forum/index.ph...ailblazer-2-blade-composite-prop.1536/page-12 posts #208 through #221. The carb heat source was similarly moved over to the #3 header with parts that look like they came from a Cessna.

With regards to the earlier A1, A1A and A1Bs, could anyone please provide info regarding problems with their exhaust system cracking at low engine hours?

The way I see it, spending $5,700 for a exhaust system that is prone to cracking isn't worth it when you add in the required service hassle of removing and replacing it every year. I can understand someone that regularly flies in a sub zero environment may want more heat than the stock system can provide and if they can't get legal paperwork to change the heat shroud as described above, then the PowerFlow is the answer.

I did take the time to make a simplified FEA model of the PowerFlow and the natural frequency of the system is ~ 100 Hz, note that if it were the combustion pulses of the engine that is exciting the system to cause cracks, it would translate to ~ 3,000 rpm. I doubt that anyone would be cruising with their engine much above 2,400 rpm (80 Hz impulse frequency) and as such it may not be the primary problem.

The shroud's flange that has a problem with cracks looks to be a poor weld quality problem. On inspection, it looks like it was TIG welded with the interior of the header tube purged with argon. What isn't being done is to back purge the flange in the area where they crack. Look at the back side of the flange and you can see the black carbon (AKA sugar) that resulted from PowerFlow's welding method. The granular disruptions could be the initiation point (stress riser) for the weld to crack to begin.

I asked the PowerFlow manager about the problem and all he said was that if they are provided proof that the aircraft had a dynamic balanced prop and that the system was removed every year to service the slip joint and that the system is in the warranty period, I could send it to them for a free repair. He would not discuss why these are cracking and whether anything different was done with their repair to prevent the cracks from forming again. My PowerFlow is out of warranty so I saw no benefit in sending it in to them instead of taking care of the problem myself. When I get a chance, I will repair the crack and properly back purge both the interior of the tubes along with the back side of the flange when doing it.

So RamBuster, unless you have a problem where you are too cold while flying your new to you Husky, I would say, "don't fix it, if it ain't broke."

 

[groshel]

I always thought a Powerflow was for more power not cabin heat.. I
do not want to spend $5K and a bunch more re-occurring Mx just to get heat.

The Husky is the only light plane I’ve been in with a substandard cabin heating system and it’s my biggest gripe with the Husky. The heat is there it’s just not getting the volume of air into the cabin. If I put my hand near the outlet..it’s hot….just no flow. It would be one thing if there was lukewarm flow but there’s almost nothing. My plastic eyeball vent in front is partially melted with a stock system but I’m always cold.

I think Thomas has it nailed by redirecting the ducting and increasing the shroud volume. Our mufflers are similar in size of my old Grumman Cheetah’s which had plenty of heat but then it had a dedicated riser from #2 cylinder for the carb heat.

Yep...there are several ways to correct this problem but buying a Powerflow system seems to be the most costly way to go.

Excel Air in Rennselar, Indiana “rebuilds” existing muffs for risers from cores. Their pics below for those of you that aren’t familiar with shrouds for the riser.

Anyway…spring time is here …no need for heat!

Chris



Carb Heat Muff for Cheetah and Traveler
These expertly rebuilt heat muffs fit like new and prevent your exhaust pipe from wearing out. Comes with new mounting tabs and hardware. Availability of this part is subject to the number of rebuildable cores we can obtain so get your order in.

Old muffs will look like this:

 

[dogday]

In addition to PowerFlow's cracking problems, I have heard that the PowerFlow exhaust increases the cylinder head temperatures a bit more than many folks are comfortable with. I only had a few hours on my Husky when I overhauled it and put Lycon's ported/flowed cylinders on with the PowerFlow and a TrailBlazer prop. There were so many changes made, there is no way I could tell what gave the performance a small boost and caused my cylinder head temps to noticeably increase. The cylinder head temperature problem was resolved by fixing the #3 baffling that blocked flow around the back of that cylinder and installing the "tractor baffle." By far, the #3 baffle mod created the most improvement for the effort and moved #3 CHT from being the warmest into second place.

Kurt stated that he didn't see much increase in performance which I have heard from others. I have the stock exhaust back on and will start flying again in a few weeks once my runway is clear of snow. If there is a significant decrease in performance with the OEM exhaust, I will post the results.

 

[Oryx]

In addition to PowerFlow's cracking problems, I have heard that the PowerFlow exhaust increases the cylinder head temperatures a bit more than many folks are comfortable with. I only had a few hours on my Husky when I overhauled it and put Lycon's ported/flowed cylinders on with the PowerFlow and a TrailBlazer prop. There were so many changes made, there is no way I could tell what gave the performance a small boost and caused my cylinder head temps to noticeably increase. The cylinder head temperature problem was resolved by fixing the #3 baffling that blocked flow around the back of that cylinder and installing the "tractor baffle." By far, the #3 baffle mod created the most improvement for the effort and moved #3 CHT from being the warmest into second place.

Kurt stated that he didn't see much increase in performance which I have heard from others. I have the stock exhaust back on and will start flying again in a few weeks once my runway is clear of snow. If there is a significant decrease in performance with the OEM exhaust, I will post the results.

Agreed with the following couple posts.

What irks me the most is PF was initially marketed as a serious performance “upgrade”. A couple years back my dad asked a rep specifically if it would increase horse power (dyno) on a Husky. The guy would not say that it would. Many others who use them say the same thing.
So after the sales job, a bunch of people signed up to purchase one and it turns out to be a nearly $6000 dollar heater enhancement.
I do believe based on other pilot reports that PF is a legitimate performance modification on certain aircraft just not the Husky.

 

[belloypilot]

If PF exhaust results in higher CHTs something has changed. Higher CHTs would be the result of increased engine power output, leaner mixtures, or a combination of the two - right?

 

[Ak Kurt]

Jack, from what I have seen the “newer” units are the ones having cracks. What is “newer” you ask, I dont know for sure but my 2012 unit cracked where my buddies 2007 unit has not. I do have another friend who’s 2007 flame tubes have burned out, this is probably a normal thing to have happen but cracks are not.

One of the Powerflow requirements for continued airworthiness is to remove the system and lubricate the joints at every annual. This should be done with any system and not just Powerflow. The Powerflow in reality doesn't require any more maintenance than any other system, they just spell it out in their instructions for continued airworthiness. All systems need lubrication and maintenance even the stock system.

In my opinion everything that Dogday mentions above is spot on. The Powerflow system has issues but I feel that the issues of some of the later stock systems are more problematic than the Powerflow issues so that is why I am running one. I think having the types of cracks the stock system has had is more problematic in flight than the types of cracks the Powerflow has been having. If Aviat can get the vendor to address and correct these cracking issues then there will be no need to go to a Powerflow system in a Husky. Hopefully the vendor has improved their product already. I would say to anyone running a stock system is keep an eye on it and if its not cracking then keep running it, if it does start cracking replace it with a new Aviat unit and hope for the best or replace it with a Powerflow unit and hope for the best also. Regardless which unit yo go with make sure you remove and lubricate the joints at every annual or every 100 hours and have your prop balanced, this will reduce the chances of cracking with either unit.

Kurt

 

[flyingjack]

Lots of great info; thanks everyone.

 

[trapper]

My stock 2003 exhaust has 1250 hours with zero issues I guess I am one of the lucky ones. I think my old A1 has way over 2000 now

 

[LOWandSLOW]

Welcome RB! Looks like that airplane is set up nicely for some up north flying. As far as advice, read the threads in this forum, a lot of great info.

If you dont already do so, try running over square, it works great especially with that MT prop. 1900-2200 RPM and 20-25 inches of MP is a great range. Slow RPM and higher MP burns a lot less gas. Dont forget to lean.

Also, Aero LED landing lights are well worth the investment, they are super bright and last forever, you will never need to mess with all the screws replacing bulbs and you can leave them on all the time to help with collision avoidance.

The Powerflow exhaust is a good especially for up north, it produces a lot more cabin heat. I did not notice the big performance improvements advertised but I did notice a little improvement, what I really noticed was the extra cabin and carb heat. Make sure to get the metal eyeball heat vents because the stock plastic vents will melt with the additional heat. Also get the Challenger (K&N) air filter if you get the Powerflow exhaust.

Those are just a few tid bits for now, read thru old posts and you will become much better educated on your fantastic airplane.

Kurt

PS where do you live in the NWT? Im originally from Alaska.

Second the metal eyeball vents.