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marktrav

Member
Hi all! I'm looking for validation for a spreadsheet I came up with to estimate the timeline and cost for building an RV-4. The only thing I know at this point is the total time to build, and the cost estimates as given on the Van's web-site. I broke it out by phase and allocated percentages of time to each phase. Do those allocations fit reality? They don't have to be exact, I'm just trying to get into the ballpark.

Another cool feature of the spreadsheet is I can enter an estimate start date, and the average number of hours I think I can work per week, and it will estimate the calendar dates for each phase. Looks like around $50K and 3.2 years would get me a nice, basic RV-4.

RV-4%20spreadsheet%20picture.PNG"



I couldnt' figure out how to attach a spreadsheet, but I at least figured out how to embed images. :D (And I think, based on preview mode, that the image is going to be too small... hmmm... look for a second post while I figure this out...)

Mark
 
I should also add...

I want to build a fastback RV-4 with the low-drag Lopresti style cowl. So, I'm sure this adds time to the Phase 3 build...

Mark
 
You forgot to factor in 2 variables. 'Life Happens' and 'What Money?'. Also add at least one year per family member.
 
Mark,

Aren't you married with at least one small child? In that situation, I believe you'd do well to average 10 hours per week unless you only sleep 4 hours a night or have some other huge advantage which lets you work on a project when the family is away or asleep. In my build, I probably averaged 500 hours a year, which is 10 hours/wk. And that was back when I was single, didn't have a dog, etc...
 
3rd variable

Mark,

Add one more variable - parts availability when you need it. The planned time increases if you waste a part and need to order a replacement or do not have next subkit available. (Re)ordering, shipping and remaking takes its toll. One more - any deviation from you plans will increase the time by at least 10%.
 
Builder experience and personality type are big factors in build time. Some folks move quickly when building, and they make very quick progress. Other over analytical folks, like me, spend many hours just pondering things, trying to find the best solution to the problem of the day. The fast mover type would have grabbed the first solution that came to mind and finished the task while I was still coming up with ten possible solutions and comparing the pros and cons of each.

The fact that you are working on this spreadsheet leads me to believe that you are the over analytical type whose build time will be at least 50% longer than average.
 
Kyle Boatright said:
Mark,

Aren't you married with at least one small child? In that situation, I believe you'd do well to average 10 hours per week unless you only sleep 4 hours a night or have some other huge advantage which lets you work on a project when the family is away or asleep. In my build, I probably averaged 500 hours a year, which is 10 hours/wk. And that was back when I was single, didn't have a dog, etc...
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Hey Kyle! Actually, two small child(s). Both two (first in years, second in months). They are both boys, so hopefully they will like rivets and tools. And 4 cats. I think the cats might be more help at this stage, but at least they don't need the attention of a dog. And at this point, I'm lucky to get 3-5 hours of sleep. I'm glad I'm not playing the role of milk truck, or I'd get less.

Mark
 
Kevin Horton said:
Builder experience and personality type are big factors in build time. Some folks move quickly when building, and they make very quick progress. Other over analytical folks, like me, spend many hours just pondering things, trying to find the best solution to the problem of the day. The fast mover type would have grabbed the first solution that came to mind and finished the task while I was still coming up with ten possible solutions and comparing the pros and cons of each.

The fact that you are working on this spreadsheet leads me to believe that you are the over analytical type whose build time will be at least 50% longer than average.
Click to expand...

Oh dear. I guess I'm going to be on the 10 year build plan. However, I don't have a kit in the garage, so the only thing I've got to play with right now is a spreadsheet. I think if I had a kit in the garage, I'd forget what a spreadsheet was.

Mark
 
You will have a real good idea what you're capable of and what your family is tolerant of after the first year. Get started and do your calculations in a year. ;)
 
Kevin Horton said:
Builder experience and personality type are big factors in build time. Some folks move quickly when building, and they make very quick progress. Other over analytical folks, like me, spend many hours just pondering things, trying to find the best solution to the problem of the day. The fast mover type would have grabbed the first solution that came to mind and finished the task while I was still coming up with ten possible solutions and comparing the pros and cons of each.

The fact that you are working on this spreadsheet leads me to believe that you are the over analytical type whose build time will be at least 50% longer than average.
Click to expand...

You make me feel so much more normal when you post stuff like that Kevin. Thanks! :)
 
marktrav said:
Does the percentage allocation to each phase look correct?
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It looks good but I would relocate 5% from phase 1 to phase 4 and would find couple percent somewhere for phase 5. FYI some RV builders are using different percentage scale something like 90% complete 90% to go :)
 
I have not been tracking my build hours, but here is my experience so far.

Got started on the RV-9A empennage 8/20/09. Finished minus tips on 10/25/09.

Started on the wings immediately after that and finished them (minus the tips and bottom skins) on 4/12/10. Missed about a month during this phase due to the holidays and business travel.

Started on the fuselage immediately after the wings and as of today I am just about ready to complete the necessary riveting to roll the canoe (less than 50% done?). Missed ~2 months of building during this phase due to travel, family stuff, flu, etc.

I work on the project almost every day. My 3 kids don't need much of my attention at their ages (15, 18, 19). Usually put in 3-4 hours an evening during the week and 8-12 hours a day on the weekends.

I'm sure my progress will slow down considerably once the expenditures for engine, prop, avionics, etc. start coming. I refuse to go into debt on this project, so it will be pay as you go. Hoping to get it done in less than 5 years. I've waited 20 years to start this project, so what is another year or two?
 
marktrav said:
Does the percentage allocation to each phase look correct?
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IMO, the percentages for the electrical and FWF sections are high. I probably had 100 hours in electrical stuff and -200 hours of FWF work. Those areas are more installation than fabrication and you don't need any helping hands. With a non-prepunched kit, I think you'll spend a lot more time on the airframe - the wings and fuselage in particular.

I do have to ask... Why a 4? Great flying airplanes, but the non prepunched kit will take 500 more hours to build and at the end of the day, an RV-4 is worth the sum of its parts. With an RV-8 (for instance), you save build time and probably have something that is worth more than the sum of its parts.
 
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Hi all! I'm looking for validation for a spreadsheet I came up with to estimate the timeline and cost for building an RV-4.


Mark,
IMHO, Your $ estimates are about right. Your time estimate (167 weeks) will work if you are able to do 15-20 hours a week.

In building my 6A, I figured if I did 20 hrs/wk I could finish in 2.5 years. I started out trying to do 20 hrs/wk and found it to be like having a part time job. In reality, I wasn't enjoying the building experience so................ I started working on the plane when I felt like it and doing other things when I didn't and that's when I really started enjoying building my plane!

All in all I averaged 10 hrs/wk. Hope this helps.
 
Kyle Boatright said:
I do have to ask... Why a 4? Great flying airplanes, but the non prepunched kit will take 500 more hours to build and at the end of the day, an RV-4 is worth the sum of its parts. With an RV-8 (for instance), you save build time and probably have something that is worth more than the sum of its parts.
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Kyle, I'd typed up this great multi-paragraph response, but this sorry-for-an-excuse listserv software decided to log me off and I lost everything. So, here's the short version.....

Based on reading alot of these posts in these forums, I see alot of -4's being built by people "trading down" from -8's, Rockets and others. Seems like the flying qualities outweigh the downsides of build time and resale. Plus, it seems like it's cheaper to build and maintain, which is a big part of the reason for me to build.

Of course, I may change my mind after a ride in a -4 or a -8 or a -7. I need my wife's blessing and she might want a -7 (or she may just tolerate my insanity, which is OK as well!). If you know of anyone who is willing to give a ride in our neck of the woods, let me know!

Mark
 
marktrav said:
Kyle, I'd typed up this great multi-paragraph response, but this sorry-for-an-excuse listserv software decided to log me off and I lost everything. So, here's the short version.....

Based on reading alot of these posts in these forums, I see alot of -4's being built by people "trading down" from -8's, Rockets and others. Seems like the flying qualities outweigh the downsides of build time and resale. Plus, it seems like it's cheaper to build and maintain, which is a big part of the reason for me to build.

Of course, I may change my mind after a ride in a -4 or a -8 or a -7. I need my wife's blessing and she might want a -7 (or she may just tolerate my insanity, which is OK as well!). If you know of anyone who is willing to give a ride in our neck of the woods, let me know!

Mark
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I can give you a ride in my -6, which is the sportier, better flying version of the -7. And I can probably get you in the backseat of either a -4 or a -8 up at VPC.

Realistically, a ride in the -6 will be pretty representative of a -4, and you'll get to ride up front.
 
Your position sounds just like mine when I started building - 13 years ago!

I now have a fantastic RV-6 with 10.5 hours on it waiting in the hanger until I can get the house finished for my yougest daughter's 21st birthday - a big event in this part of the world.

How long to build - IMHO it depends on your priorities - is your family your no 1 priority or is it an RV-4? Sounds to me like the spreadsheet might be part of the approval process with your wife... in which case the priority is with family.

Alternatively, you can just simply build the RV-4 and torch the relationship, you become a lonely person with an aeroplane. Cool for some.

As Kevin said it is also about how you approach the building - if you are a professional engineer or master technician - you may be prone to over think the building process. The internet is a big trap for this - use it to solve problems - not to explore the scope of options available to you.

If you have a technical trade background - these people seem to be the quickest - they just 'doit' and 12 months later it's done.

My Empennage took me 1 year to build - about 7.5%. I have a good friend who regularly builds RVs - he can knock an empennage out in about 3 weeks (RV-4 style that is). Use the Empennage to test yourself - if you can build it in 17 weeks as you have in your spreadsheet in my opinion you will be on track for a 4 to 4.5 year build.

If you 'know' you are going to build an aeroplane - just start - forget about the build time and enjoy the process. You will not be alone.

Good luck,
Doug Gray
 
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