Weight and Balance concerns
Posted: Sun Mar 19, 2017 10:23 am
by Area 51%
Looking ahead to an engine installation, (It will be a while. Just lining up ducks) I gather the Waiex is prone to being tail-heavy.
So far I’ve lost 3lbs by making an aluminum fuel tank, and have the potential of taking off more than a couple of pounds with a lithium battery. I’m guessing a total weight savings of 10 plus lbs. All of this, of course, only makes the CG issues worse.
To offset the lost weight in the nose, and to address some of the structural issues found in a clearanced stock VW block, my plan calls for the use of an aluminum crankcase, manufactured with stroker crankshafts in mind and wider cylinder bosses. The aluminum cases weigh in at about 45lbs.
Is there anyone out there that hasn’t assembled their engine yet that is willing to weigh their magnesium case and report back? The difference may be greater than I expect and might not be a viable option.
Fat, dumb, and happy here @Area 51%
Re: Weight and Balance concerns
Posted: Sun Mar 19, 2017 10:54 am
by radfordc
https://www.kustom1warehouse.net/New_16 … 101025.htm
This says that the mag case is 17 lbs lighter than an aluminum case. That matches everything I’ve read before.
Re: Weight and Balance concerns
Posted: Sun Mar 19, 2017 6:12 pm
by rizzz
I have a standard magnesium case but if I were to do it again, I’d probably take the weight hit go with a CB performance aluminum case.
They come drilled & tapped for full flow and HVX mod ready, and are filled in behind #3 from the factory.
Only downside (apart from the extra weight) is that they tend to run slightly hotter than standard magnesium cases, or so I’ve been told.
Re: Weight and Balance concerns
Posted: Mon Mar 20, 2017 12:51 pm
by vwglenn
If I were to build a VW powered plane, I’d go with an aluminium case for strength and added piece of mind.
Re: Weight and Balance concerns
Posted: Tue Mar 21, 2017 6:35 am
by Area 51%
Not that I’ve spent a lot of time searching, but the only cases I have come across are the EMPI units. Are there others out there?
Also, what is the HVX mod? I’m familiar with the “Bubble Top” and the #3 modifications to the aluminium blocks.
Thanks for the thoughts.
Re: Weight and Balance concerns
Posted: Tue Mar 21, 2017 12:50 pm
by vwglenn
I’m not sure where the majority of the cases come from these days (although I did hear they were going to or stopped making magnesium cases). I would imagine a great deal of aluminum cases are Empi which usually means “made in China”. In a lot VW circles Empi is synonymous with garbage. I’ve found that to only be partially true. I would thoroughly inspect any VW part I was about to put on my plane. Chinese manufacturers aren’t known for their quality control. (think sand still in the parts form the casting process)
The HVX mod is an attempt to get the VW to throw more oil out to the heads to reduce temps if memory serves which I believe was for racing applications. You might think “Racing stuff? I want that!!!” but a good deal of the mods are aimed at high revving engines turning 5000+ RPM. I don’t know that many of them would be applicable to an aircraft engine spinning at a slower rate.
I like the aluminum case for a couple reasons…It won’t go up like a sparkler if something gets too hot (burning magnesium will turn night into daylight). Aluminum is a stronger than mag which should withstand the stresses of the aircraft application better.
All just my opinion.
Re: Weight and Balance concerns
Posted: Tue Mar 21, 2017 5:18 pm
by radfordc
vwglenn wrote:The HVX mod is an attempt to get the VW to throw more oil out to the heads to reduce temps if memory serves which I believe was for racing applications.
Not for racing… http://bobhooversblog.blogspot.com/2007 … -mods.html
Re: Weight and Balance concerns
Posted: Tue Mar 21, 2017 11:11 pm
by vigilant104
vwglenn wrote:I’m not sure where the majority of the cases come from these days (although I did hear they were going to or stopped making magnesium cases).
That was a rumor a few years ago, that production of the Mg case would end very soon. In fact, the magnesium cases are still being produced in Brazil.
Re: Weight and Balance concerns
Posted: Thu Mar 23, 2017 6:14 am
by Area 51%
I have a VW based street buggy, and am no stranger to EMPI parts, both good and bad. As with all Chinese manufactured things, you must inspect and/or fix them before use.
I’m still leaning toward the aluminum case, however, as it appears the U.S. machinists working for Sonex might have dual citizenship anyway. The examples that jump to mind are the clearances that were cut into the oil galleys, eccentric prop hubs, and spitting spark plugs as if they were watermelon seeds.
Back to my original thought. Does an extra 10lbs in the engine compartment do any harm to weight and balance in a Waiex?
Haio-Haio-Chi from Area 51%
Re: Weight and Balance concerns
Posted: Thu Mar 23, 2017 9:22 am
by MichaelFarley56
This is of course my two cents only, so please take it for what it’s worth…
Personally, I don’t see how adding 10 lbs to the engine compartment will make much of a difference. As long as you can keep the engine less than the 200 lb max weight as recommended by Sonex, I’d guess you’re okay.
When I installed the turbo on my AeroVee, it was a weight addition of approximately 22 lbs and the airplane flew great. On a Waiex, shifting the C.G. forward slightly actually made things a little more stable.
Again, just my two cents!
Re: Weight and Balance concerns
Posted: Thu Mar 23, 2017 11:54 am
by WaiexN143NM
Hi all ,
I agree with mike. Keep the wt forward on the waiex up to 200 lb. fwf. I always top off the fuel before flying. Keeps cg forward. Watch what you put in baggage area!
WaiexN143NM
Michael
Re: Weight and Balance concerns
Posted: Thu Mar 23, 2017 4:39 pm
by markschaible
Hello SonexBuilders.net
We’d like to cover several items discussed in this thread:
Aluminum Cases: In 2013 Sonex Aircraft acquired an aluminum Type 1 crankcase and weighed it side-by-side against our mag case. The weight difference was far-more than 10 lbs. Here are the results:
Magnesium Crankcase: 24 lbs.
Aluminum CrankCase: 43.2 lbs.
Weight difference between Aluminum and Mag Case: 19.2 lbs!
See the following pictures of these weights:

Keep in-mind that, although an aluminum case build-up of the AeroVee may still fit within the Sonex’s 200 lb FWF weight limit, it is dead weight that is not doing anything for you in-terms of providing additional power. The increased weight of an AeroVee Turbo, UL Power or Jabiru 3300 installation offset their weight penalties with increased horsepower and 50 lbs of allowable gross weight increase due to the increased power on-tap.
Case Machining and Heads: Sonex Aircraft has ended its vendor relationship with MOFOCO. Cases are now being machined by the original case supplier in Brazil — the supplier that casts and machines all Type 1 magnesium cases for all aircooled VW parts suppliers worldwide. High quality heads are now being sourced from EMPI, and the job of machining of the secondary ignition spark plug holes has been returned to our pre-MOFOCO machining supplier.
Although there have been an unacceptable frequency of service issues with MOFOCO heads, it’s important to note that the majority of heads supplied by MOFOCO have been good. If you have MOFOCO heads and they are working well, don’t fix something that’s not broken. If you have service issues with your MOFOCO heads, we would encourage builders to contact MOFOCO directly to have your service issues addressed. If you do not receive satisfactory service from MOFOCO, please be sure to let us know via our technical support email address.
Prop Hubs: As you’ve seen in other threads on this forum, there have been a few cases of excessive prop hub runout found. As a percentage of total number of hubs produced, the number of instances of this issue have been very isolated. We are reviewing the machining and quality check processes for prop hubs with our machining supplier and our staff to help prevent future occurrences. If you have interference of the prop hub shaft with the nose of the crankcase and/or have observed runout at the face of the prop hub flange or excessive prop tracking issues, please contact our tech support email address with runout measurements and any other relevant data and we’ll take care of you.
A General Note about VW Conversions: As we’ve posted to Sonex and AeroVee forums many times through the years, it’s important to keep in-mind that the AeroVee and all of its competitors in the VW aircraft conversion world have the same set of core parts suppliers available to choose from. The beauty of the VW aircraft conversion and the key to it’s low cost is that there are so many parts suppliers to choose from, however, the worldwide supply of parts and the quality of parts supplied by vendors is often a moving target. Challenges in the core parts supply line are also challenges for our competitors. We work very actively to source the most-appropriate combination of core parts for the application, balancing economy with quality to best suit the mission of the AeroVee. Sometimes subtle changes in supplied parts from vendors don’t effect quality, but they do create some confusion for builders (such as the most-recent AeroVee manual revision addressing the proper identification of connecting rod orientation). Note that many parts offered in the aircooled VW racing aftermarket are for “high-rev” applications and are therefore overkill for an aircraft conversion, which operates in a much-lower RPM range. We focus more on the low-RPM, higher torque “off road” configuration and components. If considering alternative parts for your AeroVee, use caution! There aren’t many parts in the VW supply chain that we haven’t tried at one time or another in our 40+ year history working with VW conversions, and there’s usually a reason why the AeroVee doesn’t use a given part.
As always, please feel free to contact us directly with your questions at the sources listed below.
Regards,
Mark Schaible
General Manager
Sonex Aircraft, LLC
phone: 920-231-8297
fax: 920-426-8333
http://www.SonexAircraft.com
http://www.AeroConversions.com
Sales Info: sales@sonexaircraft.com
Orders: orders@sonexaircraft.com
Accounting: accounting@sonexaircraft.com
Tech Support: tech@sonexaircraft.com
Build a Sonex Aircraft in Your School!
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Re: Weight and Balance concerns
Posted: Thu Mar 23, 2017 8:41 pm
by kmacht
“If you have service issues with your MOFOCO heads, we would encourage builders to contact MOFOCO directly to have your service issues addressed. If you do not receive satisfactory service from MOFOCO, please be sure to let us know via our technical support email address.”
WOW. I can’t believe sonex is actually telling builders that have problems with a product they bought from Sonex to go to their supplier and try to address any issues. Why exactly are we paying marked up prices from sonex if they aren’t going to directly support the product they are selling? It’s bad enough to not have a robust quality inspection process but to then pass customer quality issues off to your supplier is just unconscionable.
Keith
#554
Re: Weight and Balance concerns
Posted: Thu Mar 23, 2017 11:26 pm
by markschaible
to then pass customer quality issues off to your supplier is just unconscionable.
Unconscionable? Not at-all. It’s just the fastest-most efficient way for you to receive service for your heads when it comes to MOFOCO. When we began the relationship with MOFOCO, they were insistent that they wanted their logo to remain on the heads because they were very proud to be a supplier for the AeroVee. With that voluntary identification by the vendor comes the customer’s ability to go to them directly for service, and the vendor’s responsibility to provide that service. If you’re more comfortable bringing MOFOCO head service issues to Sonex tech support first, then by all means do so!
Re: Weight and Balance concerns
Posted: Thu Mar 23, 2017 11:43 pm
by wlarson861
In defense of Sonex’s position with MOFOCO, I understand that they have now ended their business relationship with MOFOCO and therefore have much less influence on that company than the customer who now holds the defective product. When I bought replacement heads from Sonex last summer they were MOFOCO brand. Installing the spark plugs for the first time I spun a spark plug. I sent them back to Sonex who had MOFOCO put Timeserts in all the spark plug holes and shipped them for nothing. At the time they were still doing business with MOFOCO, they said they were forcing MOFOCO to put Timeserts in all their current inventory and any future products supplied to Sonex. Obviously MOFOCO still didn’t produce a quality product and Sonex has moved on as they should. That being said, Sonex has no more leverage over the supplier, they can no longer threaten loss of future business as that option has already been exercised. We on the other hand, as end consumers, have the power and right to demand the company make good on their product. As the old business saying goes: " Do a good job for a customer and he will tell his friends, do a bad job and he’ll tell everybody!"
Re: Weight and Balance concerns
Posted: Sat Mar 25, 2017 7:09 am
by Area 51%
Mark,
I guess you missed the part in my original post about the installation of a light-weight battery, coupled with my aluminum fuel tank, reducing the “normal” weight in the engine compartment by 10lbs or more, making the “NET” gain only 10lbs or so. Thanks for the actual comparison by the way. Those were the numbers I was looking for.
As far as dead weight doing nothing, that’s what I think about when I hear of dive weights being added fore or aft. Not something that appears (at least at first blush) to be a superior component that has a weight penalty attached. It looks as if I’m going to “need” some extra weight in the nose any way, and the aluminum case seemed to be a good direction to head.
On to balancing quality with economy, depending who you talk to, my butt is worth the cost of the best VW parts available (Not worth the cost of a Jabiru or Rotax however). So, maybe it’s time for Sonex to put together a “premium” VW engine package for those of us that haven’t the time to explore and experiment with all possible components and don’t want to hold our breath to see if our parts are in the “majority” category. It cost me $1000 to replace a crappy fuel tank. I’m willing to throw a few dollars at, lets say, a better light-weight valve train.
Hoping the Yugo-Aero-Mod gets to the market soon here @ Area 51%
Re: Weight and Balance concerns
Posted: Sat Mar 25, 2017 8:30 am
by samiam
Area 51% wrote:Mark,
I guess you missed the part in my original post about the installation of a light-weight battery, coupled with my aluminum fuel tank, reducing the “normal” weight in the engine compartment by 10lbs or more, making the “NET” gain only 10lbs or so. Thanks for the actual comparison by the way. Those were the numbers I was looking for.
As far as dead weight doing nothing, that’s what I think about when I hear of dive weights being added fore or aft. Not something that appears (at least at first blush) to be a superior component that has a weight penalty attached. It looks as if I’m going to “need” some extra weight in the nose any way, and the aluminum case seemed to be a good direction to head.
On to balancing quality with economy, depending who you talk to, my butt is worth the cost of the best VW parts available (Not worth the cost of a Jabiru or Rotax however). So, maybe it’s time for Sonex to put together a “premium” VW engine package for those of us that haven’t the time to explore and experiment with all possible components and don’t want to hold our breath to see if our parts are in the “majority” category. It cost me $1000 to replace a crappy fuel tank. I’m willing to throw a few dollars at, lets say, a better light-weight valve train.
Hoping the Yugo-Aero-Mod gets to the market soon here @ Area 51%
Area 51%,
I am by no means a Sonex factory defender, but I want to challenge you on some of your viewpoints here. I think you are approaching this from the perspective that you can build the airplane better than the way Sonex recommends. That may be true, but this is a product that they have spent years developing and testing with aircraft designers and engineers.
Just a few points to challenge you on:
-
Why are you assuming the aluminum case will be better? Are you assuming it will be stronger? Have you tested it? What problems with the current Aerovee setup has it been proven to solve? Do you know what effect it will have on cooling? If anything, reports on aluminum cases show worse oil cooling. You are trading 20 pounds of weight for a case that may or may not be superior and could introduce new problems in your build. This is experimental aviation, so you are free to experiment as you wish, but I don’t think that it’s fair to expect Sonex to support or sell this setup.
-
“my butt is worth the cost of the best VW parts available (Not worth the cost of a Jabiru or Rotax however). So, maybe it’s time for Sonex to put together a “premium” VW engine package for those of us that haven’t the time to explore and experiment with all possible components and don’t want to hold our breath to see if our parts are in the “majority” category.”
I’m not sure what you mean by this. I think the package you are asking for is exactly what the Aerovee offers. It’s a set of proven, tested VW products that balance reliable engine performance with affordability. If you want something that you feel is more reliable, you will have to spend more money. It’s your risk and your decision. But it’s a decision you knew about when you started the Sonex.
- “It cost me $1000 to replace a crappy fuel tank.” The molded fuel tank has had its issues with fittings, but on a whole it is preferable to aluminum tanks. The molded fuel tank is more crashworthy. I wouldn’t pay extra for something that is less safe, personally. And this goes against your previously stated philosophy that you will pay a “premium” to get better quality parts.
Again, I’m by no means a Sonex factory goon. I wish that the factory supported my decision to go with the Corvair more than they do, but so be it. It’s their product, and I respect that. I also respect that tons of thought and testing went into this design. If I think of a way that it would be improved, chances are Sonex has as well and they have decided against it for various reasons.
I hope that none of this sounds cantankerous, as I’m just trying to challenge these ideas in the name of safety. Best of luck in your build!
Re: Weight and Balance concerns
Posted: Sat Mar 25, 2017 1:37 pm
by NWade
kmacht wrote:"WOW. I can’t believe sonex is actually telling builders that have problems with a product they bought from Sonex to go to their supplier and try to address any issues.
Keith -
While I’ve had my own frustrations with parts-quality lately, I want to respectfully disagree with your assertion here. Haven’t you ever bought a product at a store, and when you get it home you find a card inside the product that says “WAIT! DO NOT RETURN THIS PRODUCT TO THE STORE”; and then it proceeds to give you a customer service number to call?
This is essentially what Sonex is asking you to do in this case: You bought the product from them, but they’re asking you to deal with the manufacturer for support, not the “store” you bought it from.
Is it annoying? Yes.
Is it unprecedented or does it illustrate some bad or unusual practice? No, not at all.
IMHO, Sonex needs to reinforce the idea of the AeroVee being a “kit” and not an engine. I think a lot of us (myself included) tend to think of it as a finished product that we’re simply assembling ourselves as a cost/labor-saving move. But I’ve come around to the idea that its not healthy to think of the product in that way. I don’t ascribe any evil motives to what they’ve done, but I think the way the AeroVee is marketed and sold gives the impression that its a single finished product that you’re buying from a manufacturer. But that’s not what it is! You don’t buy an “AeroVee Engine” just like you don’t buy a “Sonex Airplane”. What AeroConversions sells is a package of parts that have been tested and are known to work well together, and its being re-sold as a bundle for your convenience (so you don’t have to track down and source all of these parts yourself). I’ve fallen into the trap of thinking about it like a single product myself, and while I wish it was a simple drop-in product (like buying a completed factory engine for a car) - it simply isn’t.
We can wish for a simple low-cost low-weight 100hp aircraft engine that’s ready off-the-shelf; but the market just doesn’t offer that right now. There are competitors to the 80hp AeroVee that people can buy, as long as they’re willing to trust those vendors to have properly inspected, tested, and assembled that engine. And that they used parts-suppliers that are equal-to or better-than what AeroConversions sells. But without tearing down the completed engine and inspecting the parts, there’s no way to know for sure. shrug
–Noel
Re: Weight and Balance concerns
Posted: Sat Mar 25, 2017 5:42 pm
by Fastcapy
My question regarding parts on the Aerovee is this. How much are they testing these parts? I mean first they had CB heads for a long time. Then they switched to the Mofoco heads. People were having a lot of issues with those heads. How many of their motors had those heads and how many hours did they put on them to test them? How many heads have they tried? Just one set, a couple sets? Now they are using EMPI heads? How much testing was done using those heads? Not just test cell testing either, real world flying testing.
It really seems like it is more of a thing about cost savings and profitability rather than finding the best quality parts/components.
I also think that if I am buying a kit I should have faith that the parts are of a known quality and tested thoroughly before being sold as a kit. Not just components that will work and were cheaper.
Re: Weight and Balance concerns
Posted: Sat Mar 25, 2017 9:35 pm
by kevinh
Slightly off topic but what problems are people seeing with the mofoco heads? (i.e. what should I watch for when I assemble my August 2016 edition aerovee turbo 
)
Re: Weight and Balance concerns
Posted: Sat Mar 25, 2017 11:36 pm
by wlarson861
Slightly off topic but what problems are people seeing with the mofoco heads? (i.e. what should I watch for when I assemble my August 2016 edition aerovee turbo
A common problem was the one I had, the spark plug holes were tapped incorrectly, reportedly due to the use of worn tooling. When I installed the spark plugs the fist time I spun the lower right hole. Sonex took care of the problem and replaced both heads with new heads that had Timeserts in each spark plug hole. Check your heads and make sure the Timeserts are present, if not contact Sonex or MOFOCO directly. When I had my problems Sonex said they were having Timeserts installed in all MOFOCO heads they sell. You will also need to use a spacer under the intake manifold to raise the intake elbows to clear the rear upper spark plugs.
Re: Weight and Balance concerns
Posted: Sun Mar 26, 2017 12:19 pm
by Sonex1517
markschaible wrote:
to then pass customer quality issues off to your supplier is just unconscionable.
Unconscionable? Not at-all. It’s just the fastest-most efficient way for you to receive service for your heads when it comes to MOFOCO. When we began the relationship with MOFOCO, they were insistent that they wanted their logo to remain on the heads because they were very proud to be a supplier for the AeroVee. With that voluntary identification by the vendor comes the customer’s ability to go to them directly for service, and the vendor’s responsibility to provide that service. If you’re more comfortable bringing MOFOCO head service issues to Sonex tech support first, then by all means do so!
So, as a turbo owner, I have to assume this policy extends to other engine parts. Like the turbo.
Should we contact the turbo manufacturer directly Mark?
Re: Weight and Balance concerns
Posted: Sun Mar 26, 2017 6:36 pm
by rizzz
markschaible wrote:…
Keep in-mind that, although an aluminum case build-up of the AeroVee may still fit within the Sonex’s 200 lb FWF weight limit, it is dead weight that is not doing anything for you in-terms of providing additional power.
…
I agree it does not do anything in terms of power, however I would not call it dead weight either.
Magnesium alloy work-hardens over time, that is a fact.
The magnesium cases will therefore eventually develop cracks.
I don’t believe we’re talking instant catastrophic failure cracks, they start off very small often around the case savers and you’ll notice little oil leaks long before it becomes a potentially dangerous situation.
Most data on how long it takes before cracks occur comes from the old RevMasters as they’ve been around the longest, and it seems to suggest that it can start to occur somewhere around the 500 hour mark on those engines. Just have a look on the Revmaster & VW conversion forums.
There isn’t much info available on how long it takes before this happens in case of the AeroVee but it should be similar, I’ve found one AeroVee example that had 490 hours on it when a crack developed. (see http://www.sonerai.net/smf/index.php?topic=3553.0).
All this said, 500 hours is a lot and given the price of these cases, it’s not that big a drama to have to replace it after 500 hours.
Re: Weight and Balance concerns
Posted: Sun Mar 26, 2017 9:30 pm
by Area 51%
Jeeeeeeez…all I wanted to know is if 10 extra pounds on the nose of a Waiex was detrimental.
Don’t get me started on the fuel tank again. I couldn’t even give that misshapen piece of plastic waste away .
Enjoying the build with both eyes WIDE open here @ Area 51%