New member with a question

[tsb]

Good afternoon - I am a new member, but have been lurking here on and off for some time.

I have been collecting HP calculators for about 5 years and recently came across a 41CV that was modified by Sikorsky Aircraft as a weight, balance, and performance calculator for the CH-53E helicopter used by the US Navy. It has two custom ROM modules, a custom bezel in place of the standard HP, some black painted over keys, and a Sikorsky rear label. The label indicating the model is blank and it does not appear that one was ever installed. I have found reference to this unit being developed, but can't find any other information. Has anyone ever seen this before?

[Andres]

I suggest you may look for information about the special "Blacknut" version of the HP 41, (sold as a platform for specific applications) and see if your unit belongs to that class.

[Massimo Gnerucci]

(04-04-2020 04:20 PM)Andres Wrote:  I"Blacknut"

Blanknut

[tsb]

Thank you both for your replies.

I don't think that it is a blanknut. The keys are painted over - some just on the sloped face, some completely.

I'm in the process of contacting the Sikorsky Archives too for any information they may have.

[rprosperi]

Please post some photos, including close-ups of the keyboard.

[Andres]

OK Massimo, I have seen examples of both spellings but it seems blanknut is the proper one. My mistake.

(04-04-2020 05:23 PM)Massimo Gnerucci Wrote:  

(04-04-2020 04:20 PM)Andres Wrote:  I"Blacknut"

Blanknut

[tsb]

           

[tsb]

   

[rprosperi]

Thanks for the photos tsb!

I don't think I've ever seen HP key faces painted like that and a custom label on the rear is quite rare as well.

Seems to be quite unusual and rare in general, it's not on Matthias' module list.

The CH-53E first flew in the early 80's but it's still in service with USMC, so hard to pin down when it was made; hopefully Sikorsky will reply and provide some info, but I wouldn't count on anything soon. Besides the COVID crisis, aerospace companies have been less and less responsive to such requests in recent years, many no longer retain historians and archive staff at all.

[SlideRule]

An excerpt from Programmable Hand-Held Calculators in the Operating Forces of the Marine Corps, Naval Postgraduate School, Maser's Thesis, DTIC-ADA110793, MAR 1981, 103 pgs.

"ABSTRACT
    This thesis provides usage and cost data on programable hand-held calculators (PHHC's) in the operating forces of the U. S. Marine Corps (USMC) … In February 1981 Naval Air Systems Command began reviewing a proposal to provide a PHHC for the CH-53E … systems is described, and available cost information is analyzed. In order to do their jobs faster and more accurately, several individuals have written or purchased software for their personal PHHC's … examples which have application in the USMC are presented and explained.
…
                III. FORMAL PROGRAMS UNDER DEVELOPMENT
A. AVIATION APPLICATION
    1. The Marine Corps/Navy CH-53E Heavy Lift Helicopter Naval regulation requires that certain categories of transport aircraft be provided with a system for calculating center of gravity under all possible load conditions. In the past this has been accomplished by procuring, at considerable cost, a specially designed slide rule. In May of 1980 Naval Air Systems Command requested that Sikorsky Aircraft submit an engineering change proposal to the CH-53E procurement contract which would substitute a PHHC for the center-of -gravity slide rule. The request stated, "Electronic calculators are available for approximately the same price as the MIL-C-6092A balance computer." [Ref. 11] A CH-53E calculator similar in function to the AV-8A calculator would be able to do certain performance calculations in addition to the center-of-gravity computations because the latter would only use a portion of the 5000 steps available in a TI-58 module.
    The Sikorsky proposal probably would have been quickly submitted except for one development. That development was Hewlett-Packard's newest PHHC, the HP-41C. Its enhanced alphanumeric capability, increased storage capacity, and constant memory caused Sikorsky and Naval Air Systems Command to agree that Sikorsky should take the additional time necessary to evaluate this new PHHC and how it could be employed in a flight planning decision support system role for the CH-53E. Accordingly, Naval Air Systems Command now expects Sikorsky will, during February of 1981, submit two proposals: one for using a TI-58 and one for using an HP-41C. Naval Air Systems Commmand will evaluate both proposals and will select the one with the higher benefit-to-cost ratio."
pgs. 29-30

BEST!
SlideRule

[tsb]

Yes, thank you SlideRule. I had already found that thesis document. The calculator dates to the 31st week of 1982 so the timeline for this unit follows the text.

[BobVA]

Cool, thanks for posting that.

I'm curious what's under the front overlay? The regular 41C markings?

The lack of a serial number may indicate this was one of the test/evaluation units, which would also explain the painted out keys. (They may have planned to shift to a Blanknut when/if it went into production, but perhaps already had some 41c's handy for the prototype.)

[tsb]

As far as I can tell the typical 41 bezel is not under the overlay. This overlay is glued to the case. So it looks like Sikorsky got a unit without labels and then did their own "assembly".

I have a few other oddball/interesting HP calculators that I will get around to posting.

[CY-CL]

Yes please, show us your other special HP's.

Thanks!

(04-07-2020 12:39 AM)tsb Wrote:  As far as I can tell the typical 41 bezel is not under the overlay. This overlay is glued to the case. So it looks like Sikorsky got a unit without labels and then did their own "assembly".

I have a few other oddball/interesting HP calculators that I will get around to posting.

[tsb]

This is a 17B with an interesting serial number. I've wondered if the J. Gannon was John Gannon, the general manager of the Computer Peripherals Bristol Division.        

[rprosperi]

Could well be!

s/n that start with 0000A... or 9999A.... were used for NFS prototypes and test units (internal, key volume customers and vendors (e.g. manuals and 3rd part books)).

[Massimo Gnerucci]

(04-08-2020 12:30 AM)rprosperi Wrote:  Could well be!

s/n that start with 0000A... or 9999A.... were used for NFS prototypes and test units (internal, key volume customers and vendors (e.g. manuals and 3rd part books)).

My 17C has no serial # on its clear bottom case.

[Didier Lachieze]

(04-08-2020 12:30 AM)rprosperi Wrote:  s/n that start with 0000A... or 9999A.... were used for NFS prototypes and test units (internal, key volume customers and vendors (e.g. manuals and 3rd part books)).

Also, the self test result picture has "PP1" at the right of the display. I don't have this on my 17B, just "OK-17B-I".
PP1 could mean "Production Prototype 1"

[rprosperi]

(04-08-2020 06:29 AM)Massimo Gnerucci Wrote:  

(04-08-2020 12:30 AM)rprosperi Wrote:  Could well be!

s/n that start with 0000A... or 9999A.... were used for NFS prototypes and test units (internal, key volume customers and vendors (e.g. manuals and 3rd part books)).

My 17C has no serial # on its clear bottom case.

Don't believe I've seen a 17C. Can you post a photo of the top of the unit? Did you get this back in the day, and if so do you know much about its provenance?

[rprosperi]

(04-08-2020 08:21 AM)Didier Lachieze Wrote:  

(04-08-2020 12:30 AM)rprosperi Wrote:  s/n that start with 0000A... or 9999A.... were used for NFS prototypes and test units (internal, key volume customers and vendors (e.g. manuals and 3rd part books)).

Also, the self test result picture has "PP1" at the right of the display. I don't have this on my 17B, just "OK-17B-I".
PP1 could mean "Production Prototype 1"

Or, possibly "Pre-Production batch 1"? The finish level seems to be well past prototype stage, and it seems from Massimo's unit that prototypes were called 17C.