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From: Charlie England <ceengland@bellsouth.net>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Tue, April 26, 2011 5:06:54 PM
Subject: [FlyRotary] Re: Mistral 'Like' Intake

2nd Kelly's opinion. the info I have said type 2 was for engines with *extended hub* constant speed prop (~2 1/2" beyond a normal constant speed), which moves the cg forward a lot. Van's no longer even supplies type 2 mounts because they are so rare.

IMO, the only reason to do dynafocal at all is because the mounts are so common. the old 'conical' style mount (4 parallel bolts) would be just fine for a rotary with its inherently smooth operation. The reason Lyc did the dynafocal was an attempt to damp their flat 4's horrendous vibration pattern (not that effective...). The conical mount Lyc motors can be converted to dynafocal by an engine shop, implying that the bolt circle is virtually identical. The downside to dynafocal is that the rubbers cost about a factor of 10-15 more money than conical mount rubbers. Less than $30 for a set of conical; $300-$500 for dynafocal.

I still have available the dyna ring off my original RV motor mount, if there's a scanning shop in Jackson MS. If you can find a shop, let me know & I'll take it there for a scan.

To address the concern about attachment strength: with a new housing, it should be relatively simple to add a piece to grab the top of the middle iron or even the bellhousing flange top bolts if you're really paranoid. I'm no engineer, but I'd think that there is plenty of bolt & aluminum area to take the shear loads; the only question in my mind would be the bolts at the top that will be in tension in the cast iron casting. I have a hard time believing that 6 gs could stretch the 4 or 5 bolts across the top of the 'stack' enough to affect the engine, at the relatively low power levels that will be used in a/c. (I'm strictly talking about 2 rotor engines, not the 3+ rotor versions.)

Charlie

On 4/26/2011 9:04 AM, Kelly Troyer wrote:

Jarrett,

 

     The "Mistral" 13B engine (and their 20B) CG of 9.44 and 11.73  inches respectively was complete with

all accessories and redrive (which is heavier than Tracy's RD1X re-drives of 44 lbs)................The addition

of a constant speed (with normal extension) would still keep the Type 1, 30 degree focal point of 14.373"

in front of the 13B CG (IMHO)...........The 20B CG with normal constant speed would have to be calculated

to see if it remained within the Type 1, 30 degree 14.373" focal point..............The type 2,18 degree seems

to have been used only on a specific 0-320 model installed in the twin Comanche (That does not keep your

Lancair from having this engine installed)..................

 

   

Kelly Troyer
"DYKE DELTA JD2" (Eventually)

"13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil Manifold

"TURBONETICS"_TO4E50 Turbo

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From: H & J Johnson <hjjohnson@sasktel.net>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Tue, April 26, 2011 2:36:54 AM
Subject: [FlyRotary] Re: Mistral 'Like' Intake

 Interesting. I may very well be wrong but for some reason I had it in my head [once it was jared by Bills mention of Type 2] that the Type 2's were usually used for engines w/ constant speed [due to weight] and the type 1's were used mainly for fixed pitch. [old wives tale?] I would think that due to our extra weight out front on the nose a Type 2 would be more in order. Having said that, I have no idea where the CofG on a 13B is located and how that relates to the various focal points. In addition, how adding a PSRU on the nose would impact the CofG [and or a electricl pitch prop etc].  I'll have to do some reading and see what I can dig up.  Certainly a good place to start w/ as far as a ground up design on the mounting housing.

Lynn, re: Strength of the Connection.

I remember you stating some of those points a while back. I'm wondering if, in our lower power state, these are as much a concern as they are in the racing world? It would certainly be possible to add extra parts to the install [the thickened bottom plate, or perhaps some form of a stiffener that locks the block from torque related movement front to back  { all just thoughts flashing through my brain, RHRN}. I've not heard comment about how Mistral addressed this [or if it was a concern of theirs?].

Kelly, do you know of any additional connection points [dowels or pins etc] that were needed for the instal of a Mistral housing? 

It certainly is not my first 'pick' to have a mounting housing which needs modifications to a short block, to allow it to be installed.

Jarrett Johnson
www.innovention-tech.com

 

Jarrett and Bill,

       Here is the source of my "Dynafocal" mount info...............
 

Kelly Troyer
"DYKE DELTA JD2" (Eventually)

"13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil Manifold

"TURBONETICS"_TO4E50 Turbo

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From: Kelly Troyer <keltro@att.net>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Mon, April 25, 2011 10:37:25 PM
Subject: [FlyRotary] Re: Mistral 'Like' Intake

Bill,

       My info says the Type 2 ,18 degree was introduced when O-320's were put in twin Comanches

with extra long constant speed prop extensions (for a more streamlined cowl)............This then put

the engine CG further forward so to keep the Dynafocal mount "Focal" point slightly ahead of the

engine CG the Dynafocal mount angle was reduced from 30 degrees to 18 degrees.........

 

      The Dynafocal type 1 focal point is 14.323 inches from the mounts..................The "Mistral" 13B

engine CG is 9.44 inches from the mount so should work well with the type 1, 30 degree Dynafocal

mount..............IMHO 
 

Kelly Troyer
"DYKE DELTA JD2" (Eventually)

"13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil Manifold

"TURBONETICS"_TO4E50 Turbo

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From: Bill Bradburry <bbradburry@bellsouth.net>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Mon, April 25, 2011 10:13:02 PM
Subject: [FlyRotary] Re: Mistral 'Like' Intake

There is also a Type 2 Dynafocal that I think is in more common usage.  If I recall the angle on it is 17 degrees.

 

Bill B

 

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From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Kelly Troyer
Sent: Monday, April 25, 2011 4:57 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Mistral 'Like' Intake

 

Jarrett,

 

     I found the "Dynafocal" info................Was on my other computer !!..................
 

Kelly Troyer
"DYKE DELTA JD2" (Eventually)

"13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil Manifold

"TURBONETICS"_TO4E50 Turbo

 

 

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From: H & J Johnson <hjjohnson@sasktel.net>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Mon, April 25, 2011 11:21:48 AM
Subject: [FlyRotary] Re: Mistral 'Like' Intake

The scanning should give in the tens of thousands [0.01"] or less depending on what type of equipement used etc.   That in conjunction w/ bolt hold placement that I already have [lots of collected data over the years] I should be able to duplicate the basic geometry. From there it will become a new product in that we want to make it something that works for everyone [or as many as possible] to make it a viable unit. That info, mixed w/ knowing what the 'Standard' mount geometry is should get us where we need to go.

Best regards

Jarrett Johnson
www.innovention-tech.com

----- Original Message -----

From: Kelly Troyer <keltro@att.net>

Date: Monday, April 25, 2011 10:03 am

Subject: [FlyRotary] Re: Mistral 'Like' Intake

> Jarrett,
>
>       I do not know exactly what dimensions the scanning give you
> such as bolt
> hole placement, etc.........I presumed
> that the angles of the mount ears needed for the "Dynafoal" mounts
> would be
> "Dead" on though..........
>
>
> Kelly Troyer
> "DYKE DELTA JD2" (Eventually)
> "13B ROTARY"_ Engine
> "RWS"_RD1C/EC2/EM2
> "MISTRAL"_Backplate/Oil Manifold
> "TURBONETICS"_TO4E50 Turbo
>
>
>
>
> ________________________________
> From: H & J Johnson <hjjohnson@sasktel.net>
> To: Rotary motors in aircraft <flyrotary@lancaironline.net>
> Sent: Mon, April 25, 2011 10:49:43 AM
> Subject: [FlyRotary] Re: Mistral 'Like' Intake
>
>  Excellent, now I just need to get some Dynafocal dimensions [I've
> seen it on
> the web in the past, just gotta re-locate the dimensional
> 'standards']. That in
> conjunction w/ a few scans & the picture will start to really take
> shape!
>
> I love progress :)
> I can't say Thanks enough Kelly, w/out the help of yourself and
> others it would
> be a much steeper curve to get it up to speed.
>
> Jarrett Johnson
> www.innovention-tech.com
> --  Homepage:  http://www.flyrotary.com/  Archive and UnSub:  
> http://mail.lancaironline.net:81/lists/flyrotary/List.html
>

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