Limited Access Window
Foolent Derarn
Precision foundry calculations in your pocket. No connectivity needed, no delays, just instant acoustic modeling.
Download Foolent Derarn
Version 2.1
iOS Optimized
Fully Offline
Precision foundry calculations in your pocket. No connectivity needed, no delays, just instant acoustic modeling.
Download Foolent Derarn
Three professional toolsets available now. Slot reservation expires 06.10.2026
All tools operate entirely offline. No subscription fees. No account registration required.
The physics engine behind every foundry adjustment
Built by campanologists with decades of foundry experience. Every calculation method validated against physical bell tuning results from working towers across Europe.
The acoustic modeling engine incorporates traditional bell-founding knowledge passed down through master founders, now accessible instantly on your device without internet dependency.
Professional-grade tools designed for precision foundry operations
Crown, Shoulder, Waist, Soundbow, and Lip zones independently adjustable. Each depth slider instantly recalculates all five partial frequencies showing before and after deviations in cents.
Monitor Nominal, Quint, Tierce, Prime, and Hum partials simultaneously. True window calculations show acceptable deviation range. Out-of-tune partials flagged immediately as you plan cuts.
Generate step-by-step lathe operation sequences. Each pass specifies zone, tool type, and exact millimeter depth. Checkbox tracking prevents skipped operations during foundry work.
Capture bell interior with depth markers overlaid. Reference images stay synchronized with cutting plans. Visual verification before metal removal begins prevents miscalculation errors.
The Shelf contains catalogued bell forms from Tower to Altar types. Clapper database included. Bench kit tools documented with historical context and usage notes for each instrument.
Zero internet dependency after installation. All calculations, references, and exports work in foundry environments without connectivity. No account sign-in ever required to use any feature.
Built for iOS with professional foundry requirements in mind
Foolent Derarn runs entirely on-device using native iOS frameworks. The acoustic simulation engine calculates coupled partial interactions without server dependency, providing instant feedback as you adjust zone depth sliders.
Every tuning calculation references established campanology principles validated by working bell founders. The five-partial model accounts for Hum, Prime, Tierce, Quint, and Nominal frequencies, tracking how material removal in each zone affects all partials simultaneously through physically accurate coupling equations.
Cut plan generation organizes lathe operations in optimal sequence, preventing common errors like over-cutting the soundbow before waist adjustments stabilize the Tierce. Foundry receipt export creates documentation matching historical bell-founding records, essential for restoration archive requirements.
iOS application, free installation, operational in minutes
Download Foolent DerarniOS compatibility verified. No subscription charges. No advertisements during operation. Suitable for professional foundry environments.